FR - Simplify internal cross-links

[robert-wloch-iits]

As a blib editor I want to link to other links simply by specifying the blib filename so that I do not need to know the generated relative folder paths.

As a blib editor I can see all the blibs in a flat folder. However, when editing the description and adding a link to other blibs I cannot just write [Language Foo](lf_foo). Instead, at the moment I need to be aware

• if the currently edited blib is in the same quadrant or not
• of the generated folder name of the referenced blib, if it is not in the same quadrant

Consider those excerpts of a description in lf_springboot.md:

[...] This makes it particularly valuable for [microservices architecture](../../methods-and-patterns/mp_microservices/)
[...] in modern [Java](../lf_java/) and [Kotlin](../lf_kotlin/) development.

Referencing blibs in the same quadrant can be done via ../ but when referencing blibs in other quadrants the relative path needs to go up twice and then down into a path you can see only in the browser or by looking at the config and grabbing the id of the target quadrant.

I propose a "description internal link mapper" which knows the blib filenames and looks for simple internal links like [<Whatever>](<blib_filename>) in the descriptions and replaces those with the required relative path to the target quadrant's blibs in the generated site. That proposal should turn the above example ideally to:

[...] This makes it particularly valuable for [microservices architecture](mp_microservices)
[...] in modern [Java](lf_java) and [Kotlin](lf_kotlin) development.