add missing PEPs from the google doc archive

[davemfish]

This PR adds a bunch of older PEPs that never got archived in this repo. I also re-numbered all the PEPs so they still go in chronological order. As far as I know, the PEP numbers are not referenced anywhere else, so I thought this was okay. I re-named folders in the GDrive to include PEP numbers, so hopefully new PEPs will get numbered as soon as they are submitted in the future.

I did not do a thorough check on each markdown doc to make sure all the links and figures are preserved.

[dcdenu4]

Thanks for doing this @davemfish . It looks like we do link to pep-0010 in invest/History. I don't think it's a big deal and we could retroactively update that if we wanted. Or, we could leave pep-0010 the same and bump the ones that come before to pep-0007,0008,0009.

[phargogh]

Thanks, @davemfish ! When I started numbering the PEPs at 10, my intent at the time had been that we would fill in the prior, historical PEPs at some point and then update the numbering, and 10 seemed like roughly the number of PEPs that we had accepted up to that point. I just wanted to bring that up so that whatever number we end up starting with now with a re-numbering, we are making that decision deliberately and not just because of an arbitrary call that I made some years back!