Merge kicad-library-utils into kicad-footprint-generator
Having our tooling split over multiple repos is not ideal. Changes to the CI pipelines often require syncronised commits in both repos. Also code-reuse is bad.
We wanted to make k-l-u into a proper python package anyway, integrating it into kilibs is only natural
**First steps**
* [ ] merge k-l-u into a k-f-g subdir
* [ ] minimal cleanup
* e.g. there is also a `gitlabci` folder in k-f-g that duplicates code
* [ ] patch MR pipelines
* [ ] symbols
* [ ] foootprints
* [ ] fp and 3D generator
* [ ] protect pipeline stuff with CODEOWNERS to make it harder to break the pipeline or inject crypto miners
**Then everything else can be done when there is time motivation**
* [ ] integrate k-l-u code into kilibs
* we want the code to be a proper python package that can be imported without path manipulation
* That also allows proper re use
* [ ] cleanup all the .sh scripts for ci
* Currently CI code is littlered over several places, the .yml pipeline-config, .sh scripts and wrappers, and python code
* Ideally the MR pipeline is just one python call
* [ ] refactor html_diff https://gitlab.com/kicad/libraries/kicad-library-utils/-/issues/429
* Remove all the git operations from html_diff
* Instead use the FileResolver
* Integrate step-diff into html_diff
* [ ] Use kicadModTree for kicad_mod in KLC footprint check
* Write new code that parses a kicad_mod file into a KiCadModTree object
* [ ] cleaup all k-l-u stuff
* [ ] there is a tools and a scripts folder. why?
* [ ] make the symbol generators more accessible, perhaps integrate them with the fp generators?
* [ ] Rename the repo from `kicad-footprint-generator` to `kicad-library-tools`
* [ ] Update documentation on how pipelines can be tested https://gitlab.com/groups/kicad/libraries/-/wikis/CI/Custom-KLU-branch
epic