cpp: Add bioformats component (build infrastructure and BaseMetadata)

This PR adds
- initial bioformats build infrastructure; builds and installs a shared library and headers, as well as cmake configuration for end use by third parties
- BaseMetadata class; this is a class which does nothing
- header tests

It includes placeholders in the cmake configuration for where the autogenerated metadata classes will be added as well as the static classes for when they are written.

Nothing specific to test here other than it builds; it’s not adding any real code as such, just cmake build stuff and a base class which future PRs will make use of.