Development: Extract build agent git service

[krusche]

Checklist

General

• I tested all changes and their related features with all corresponding user types 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).
• I documented the Java code using JavaDoc style.

Changes affecting Programming Exercises

• High priority: I tested all changes and their related features with all corresponding user types on a test server configured with the integrated lifecycle setup (LocalVC and LocalCI).

Motivation and Context

Currently, there is an inconsistency in build agents when using single and multi-node setup. In multi-node, they use https. In single-node, they copy the folder. This PR fixes this issue and has the added benefit of reducing the responsibilities of GitService

Description

This PR implements several structural and code improvements:

• Separate GitService and BuildJobGitService and added common functionality in AbstractGitService
• Adjust the rest of code and tests
• Change config files so that build agents have the necessary credentials to clone repos from localvc
• Reduce the amount of services used in build agents and avoid error messages when build agents are started without a cluster
• Rename and move some classes and packages for more clarity
• Improve jgit server code

Steps for Testing

Note

Test on both setups! (single node and multi node servers with ICL)

Prerequisites:

• 1 Students
• 1 Programming Exercise

1. Submit exercise and make sure that build runs
2. Clone repository and make sure that it's cloned correctly
3. Play around with features related to localvc/ci

Testserver States

Note

These badges show the state of the test servers.
Green = Currently available, Red = Currently locked

Review Progress

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

[BBesrour]

Tested on TS2 and staging

[pzdr7]

Tested on LocalCI Staging