Read/write tetgen files

[j-fu]

Allow to read/write tetgen .smesh and tetgen .ele files.
This would allow to communicate with TetGen executables from different versions, in oder to support the newly restarted development process on https://codeberg.org/TetGen/TetGen.

The general plan would be the following

• Create a method to write out .smesh files
• Make a TokenStreams.jl package based on https://github.com/WIAS-PDELib/ExtendableGrids.jl/blob/master/src/tokenstream.jl
• Add a method read in .ele files in the spirit of https://github.com/WIAS-PDELib/ExtendableGrids.jl/blob/042df1d4e2b13ddc98eb299c2a763bfd3a1b8f11/src/io.jl#L269

An alternative would be to update the c++ wrapper like in https://github.com/JuliaPackaging/Yggdrasil/blob/6e57006af5be3cb2f6c24979ab934cbd5f8d61cd/T/TetGen/cwrapper/cwrapper.cxx#L268 , however it is not clear how stable the library interface would be (but in fact is is more fun to code in Julia... )

@pjaap, @sihang0592

[ViralBShah]

@j-fu Would it be useful for you to have commit access to the repo to merge some of these PRs?

[j-fu]

Thank you for bumping this. I do have write access (via JuliaGeometry org membership), but I indeed waited for some feedback on the proposed steps, which I did not get so far.

[ViralBShah]

Perhaps @SimonDanisch or @asinghvi17? I am not a user here (but bumping the JLLs for use in PETSc in Yggdrasil).

[SimonDanisch]

I dont really use Tetgen.
@j-fu feel free to merge ;) Maybe @Kevin-Mattheus-Moerman has some opinions!

[SimonDanisch]

@j-fu I was surprised that you didnt seem to have access, so I added you specifically, which showed up as you having "mixed roles", so I deleted you again. Please ping me if that messed something up, I guess you already confirmed you have access via GeometryBasics, so unless the github UX is worse than I fear, everything should be back to normal.

[j-fu]

@j-fu I was surprised that you didnt seem to have access, so I added you specifically, which showed up as you having "mixed roles", so I deleted you again. Please ping me if that messed something up, I guess you already confirmed you have access via GeometryBasics, so unless the github UX is worse than I fear, everything should be back to normal.

Just merged a PR & triggered registrator - everything seems to be normal.