Azure packages

[danwalmsley]

• [x] Detect and install packages based on platform metadata.
• [x] Work out best way to encode package dependencies ... spec file and blob metadata?
• [x] Should we continue to use .gccsetting files or move to metadata?
• [x] Delete 7z file after download.
• [ ] Integrate existing toolchain build scripts with the uploader too.
• [x] Fix toolchains and debuggers that call GetPackageDirectory() but need to know for what version.
• [ ] Implement enter environment command, with cascading properties.
• [ ] Create an STM32 toolchain with a mix of clang and gcc.

cascading properties means inherited manifests must override properties already generated.

Maybe we have different azure containers... one for just all packages. this is where large 7z packages go, i.e. clang, gcc, etc

Then another one for toolchains, and these are just small config files saying we need package x, y,z for cc cpp, etc

Then we have meta data on packages that says this package expects x,y,z also.

Upload tool will need to generate the metadata from a spec file or something.

When a package is installed the metadata will need to be converted to a spec file, and this can be read and resolved anytime the package is accessed.