Make the KRE names represent the runtime itself instead of TFM

- Changed mono45 to Mono and removed bitness
- Renamed svr50 to CLR
- Renamed svrc50 to CoreCLR
- Changed x64 to amd64

#598
Not part of this change, but the other metadata in here looks wrong. Do we need to update it? (Version is wrong, requireLicenseAcceptance is wrong, and no license URL.)