Support columns in annotations and expose path merging algorithm

[Luro02]

Artemis seems to only support annotating an entire line. For grading, it is useful to support highlighting parts of a line.

For example, given this code and two annotations:

int three = 3;
//  ^ bad identifier
//          ^ magic number

intelligrade would highlight everything in that line, even though it could just highlight the identifier and the magic number. The autograder already exposes the column information.

This PR closes #158.

In addition to that, it closes #163.

The formatting of paths

I implemented this code in multiple codebases now, mainly intelligrade and this library share similar code. That is why I decided to write a more refined version in artemis4j that can then be used in intelligrade as well.

After about 20 hours of work later, we end up with the code in this pull request.

With this PR, I learned that lines are 0-indexed and not 1-indexed. That is confusing, and nobody even noticed that the annotation merging code assumed they were 1-indexed. The bug is now fixed, but this should be checked in intelligrade.

This PR takes care of #159 as well

This PR closes #159.

This is the before:

After this PR is merged:

[Luro02]

Regarding that, not possible. Spotless breaks when you use that.

[sonarqubecloud]

Quality Gate failed

Failed conditions
2 New issues

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[github-actions]

This PR is stale because it has been open 7 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[dfuchss]

As soon as test & CI is green, we can go ahead :)