vhdl layer remaining stuff to check

[FilMarini]

• [x] vhdl-tools by Cayetano Santos https://gitlab.com/emacs-elisp/vhdl-tools
• [ ] vhdl-capf https://github.com/sh-ow/vhdl-capf
• [x] auto-generate hdl-prj.json configuration file
• [x] auto-generate <name>.prj vhdl-mode file

[FilMarini]

on layer vhdl-layer-dev-prova the .json and .prj files are auto-generated, but the configuration messes up a lot

[FilMarini]

added function to generate support files. Now things should no longer get messy.

[FilMarini]

The hdl-prj.json generation needs to be fixed, as it does not work "out of the box"

• [x] remove symbolic links to be added to the file
• [ ] add generic flags