Simplify dind setup to allow for default docker config in workflows (#46)

### Description of the change

This switches the dind daemon to socket mode which allows default docker config in workflows.
If also simplifies the statefulset by leveraging sidecar containers and probes to replace the inline bash script

### Benefits

No need to override docker configs in workflows. Enable use of buildx

### Possible drawbacks

EOL kubernetes versions i.e before 1.29 may not support sidecar containers

### Applicable issues

- Fixes #40
- Fixes #27

### ⚠ BREAKING

Switches Docker client to socket mode instead of TCP. Any workflows that override the default docker client config will need to be updated.

### Checklist

- [x] Parameters are documented in the `values.yaml` and added to the `README.md` using [readme-generator-for-helm](https://github.com/bitnami-labs/readme-generator-for-helm)
- [x] Breaking changes are documented in the `README.md`
- [x] Helm templating unittests are added (required when changing anything in `templates` folder)
- [x] Bash unittests are added (required when changing anything in `scripts` folder)
- [x] All added template resources MUST render a namespace in metadata

Co-authored-by: ThisIsQasim <18313886+ThisIsQasim@users.noreply.github.com>
Co-authored-by: ChristopherHX <christopherhx@noreply.gitea.com>
Reviewed-on: https://gitea.com/gitea/helm-actions/pulls/46
Reviewed-by: DaanSelen <daanselen@noreply.gitea.com>
Reviewed-by: ChristopherHX <christopherhx@noreply.gitea.com>
Co-authored-by: thisisqasim <thisisqasim@noreply.gitea.com>
Co-committed-by: thisisqasim <thisisqasim@noreply.gitea.com>

unittests/helm/statefulset.yaml

@@ -74,7 +74,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[1].image
+          path: spec.template.spec.initContainers[1].image
           value: test.io/dind:x.y.z
   - it: dind uses global.imageRegistry
     template: templates/statefulset.yaml
@@ -92,7 +92,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[1].image
+          path: spec.template.spec.initContainers[1].image
           value: test.io/docker:28.3.3-dind
   - it: init uses fullOverride
     template: templates/statefulset.yaml
@@ -152,15 +152,15 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[0].env[7]
+          path: spec.template.spec.containers[0].env[4]
           value:
             name: CUSTOM_ENV
             value: "1"
       - matchRegex:
-          path: spec.template.spec.containers[0].env[8].valueFrom.fieldRef.fieldPath
+          path: spec.template.spec.containers[0].env[5].valueFrom.fieldRef.fieldPath
           pattern: "metadata\\.name"
       - matchRegex:
-          path: spec.template.spec.containers[0].env[8].name
+          path: spec.template.spec.containers[0].env[5].name
           pattern: "GITEA_RUNNER_NAME"
   - it: Has fsGroup in securityContext
     template: templates/statefulset.yaml
@@ -235,7 +235,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[0].env[3]
+          path: spec.template.spec.containers[0].env[0]
           value:
             name: GITEA_RUNNER_REGISTRATION_TOKEN
             valueFrom:
@@ -256,7 +256,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[0].env[3]
+          path: spec.template.spec.containers[0].env[0]
           value:
             name: GITEA_RUNNER_REGISTRATION_TOKEN
             valueFrom:
@@ -295,7 +295,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[0].env[4]
+          path: spec.template.spec.containers[0].env[1]
           value:
             name: GITEA_INSTANCE_URL
             value: "http://git.example.com"
@@ -323,7 +323,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[0].env[4]
+          path: spec.template.spec.containers[0].env[1]
           value:
             name: GITEA_INSTANCE_URL
             value: "https://git.example.com"
@@ -351,7 +351,7 @@ tests:
           apiVersion: apps/v1
           name: gitea-unittests-actions-act-runner
       - equal:
-          path: spec.template.spec.containers[0].env[4]
+          path: spec.template.spec.containers[0].env[1]
           value:
             name: GITEA_INSTANCE_URL
             value: "https://git.example.com:8443"
@@ -375,7 +375,7 @@ tests:
               value: "custom env value"
     asserts:
       - equal:
-          path: spec.template.spec.containers[1].env[3]
+          path: spec.template.spec.initContainers[1].env[0]
           value:
             name: "CUSTOM_ENV_NAME"
             value: "custom env value"
@@ -425,7 +425,7 @@ tests:
           name: gitea-unittests-actions-act-runner
       - contains:
           any: true
-          path: spec.template.spec.containers[1].volumeMounts
+          path: spec.template.spec.initContainers[1].volumeMounts
           content:
             mountPath: /mnt
             name: my-dind-volume