Improve parsing of module-info

[TheGoesen]

Currently this plugin uses a simple line parser. This is currently sufficient for all relevant use cases, but technically incorrect.
It is allowed to have multiple require statements in a single line (but there probably arent many people on this world doing that)
However to consider #174 a more mature parser would be nice.
On paper I would think it would be a nice solution to use a thirdparty library like https://github.com/javaparser/javaparser to do the parsing and maybe only handle the custom runtimeOnly comment using some other code. But there is also to consider performance as gradle currently will have to reparse the module-info every single run until gradle does something about the following issue:

gradle/gradle#32393

[jjohannes]

Thank you for creating this issue. You are absolutely right. The parser is incomplete and that is not good.
When I prototyped the first version of this plugin, I initially wanted to use an existing parser, but did not find anything suitable.

I wanted to have something lightweight. Where, ideally, we can only take the module-info.java parsing part of the Java grammar. Maybe we can have a look if we can cut out that part of javaparser (or another library) and reuse it. If it is a proper parser implementation, I am not too concerned about performance.

I also considered to generate a parser for the subset of syntax we need with ANTLR. But ANTLR always requires a runtime dependency for the generated code. I did not want to pull that in.

[jjohannes]

One thing to consider: CongoCC (as it does not have a runtime) using a reduced version of its Java Grammar:

• https://parsers.org/
• https://github.com/congo-cc/congo-parser-generator/blob/main/examples/java/Java.ccc