Development: Allow overriding any template resource file

[b-fein]

@coderabbitai ignore

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• This is a small issue that I tested locally and was confirmed by another developer on a test server.
• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Server

• Important: I implemented the changes with a very good performance and prevented too many (unnecessary) database calls.
• I strictly followed the server coding and design guidelines.
• I added multiple integration tests (Spring) related to the features (with a high test coverage).

Motivation and Context

The resource loader contains a as far as I can tell fairly arbitrary restriction that only files in templates/jenkins/ can be overridden by placing a identically named file next to the Artemis executable.
(arbitrary in so far as it was only needed for configurable Jenkins pipelines back then in #2306, but quite a few other features where it makes sense have been added since)

I would however also like to override other templates, e.g. the code of conduct readme.md, the data export readme.

Description

This PR removes the restriction to allow only to override files in templates/jenkins/ but allows all files in templates/ instead.

Steps for Testing

Prerequisites:

• 1 Instructor

1. Create a new programming exercise and check that the repositories contain the same initial content as usual.

Testserver States

Note

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Green = Currently available, Red = Currently locked

Review Progress

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Test Coverage

unchanged

[coderabbitai]

Actionable comments posted: 1

[julian-christl]

code lgtm