Extract raw shell/bash scripts as actual shell script files (#751)

### Description of the change

This is a preparation for #724 (bash script testing) which would be too complex to review if done there. I haven't changed the script contents.

### Benefits

Better IDE support, possibility for shell checks, tests.

### Possible drawbacks

-

### Additional information

I only extracted files that are native bash scripts. There are others, being a mix of Helm templating and shell scripts. Those scripts must be cleared first before extracting them as well.

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/751
Co-authored-by: justusbunsi <sk.bunsenbrenner@gmail.com>
Co-committed-by: justusbunsi <sk.bunsenbrenner@gmail.com>

unittests/helm/init/init_directory_structure.sh-rootless.yaml

@@ -15,7 +15,7 @@ tests:
     asserts:
       - equal:
           path: stringData["configure_gpg_environment.sh"]
-          value: |-
+          value: |
             #!/usr/bin/env bash
             set -eu
 

unittests/helm/init/init_directory_structure.sh.yaml

@@ -16,7 +16,7 @@ tests:
     asserts:
       - equal:
           path: stringData["configure_gpg_environment.sh"]
-          value: |-
+          value: |
             #!/usr/bin/env bash
             set -eu