Add ODB++ output writer functionality

[nam20485]

Essentially the "opposite" side of the parser. Once a design has been loaded, and possible modified, write the in-memory data model back out to an ODB++ file archive.

When used as shared library, the consuming application can modify the in-memory data model directly. But for use via the REST API, REST API endpoints would need to be added to POST changes back to the library's in-memory data model. Also need endpoints to tell the library to write the file out.

• serialization from memory model
• POST/PUT REST endpoints

[nam20485]

WIP started on write-out branch. See e.g. https://github.com/nam20485/OdbDesign/blob/write-out/OdbDesignLib/FileModel/IStreamSaveable.h

WIP on write-out branch merged into nam20485