Switch to ts-for-gir

Hello everyone, in order to test and improve the types of ts-for-gir, I have added it to the project. This allowed me to improve some things in ts-for-gir, since I have now done the work I do not want to withhold this from you, so here the MR.

I have adapted the following:

• I added the missing types as manual to gi/ and created corresponding issues for ts-for-gir
• I added the gir files to the repository (a git submodule might also be useful here)
• Instead of keeping the generated types in a repo, they are now generated from the gir files during the build process
• To synchronise the gir files from the developer machine with the repository, I have added a new NPM script copy:gir.
• The types are generated with the NPM script build:gir.
• A few adjustments to the code were necessary, such as forcing non-null#
• Removed missing types that now exist

@vixalien this MR might be interesting for you?