Compile SVD to binary for packaging

[BenBE]

Given that there is an XML schema for the SVD files, it might be an idea to use this information to avoid redundancy when encoding SVD files for the release.

As far as I could see in the source of this repo, the parser currently mostly tries to map the plain XML into the components according to the schema definition. As there's no need to load this structure from the XML file itself, any equivalent format that can be transformed back into this tree structure from the XML files should do.

Thus instead of releasing a package with all the 5.4GiB (which BTW compresses nicely down to ~114M with bzip2), one could replace the various tags from the schema with short binary sequences and thus safe on storage that way. Going further one could even go as far as compressing multiple files together and only storing differences between the various chips compared to some base file.

One option for the encoding may be Protobuf, another one would be EBML (cf. RFC 8794). Given how structured the data usually is, even writing a small streaming reader/writer with a proprietary format could be a viable option.