Implement namespace declarations

[Ostrzyciel]

Implementation of the new Jelly 1.1.0 feature, namespace declarations: Jelly-RDF/jelly-protobuf#12

Implemented: core API, Jena & RDF4J implementation, Jena RIOT & RDF4J Rio integrations, integration tests.

Not implemented: Pekko Streams API. This can be tackled in a separate PR.

This is implemented according to the compatibility notes in the original issue:

• Jelly-JVM will throw an exception when it encounters an unknown row type, so we cannot pretend this is the same version as 1.0. It will also by default not parse Jelly files with versions higher than the supported one.
• This feature is very "optional" and will have a very slight negative impact on performance, so it should be always disabled by default. When it's disabled, we can label the file as written with Jelly 1.0.
• Because we will disable this by default, but allow parsing both Jelly 1.0 and 1.1, this will create a soft grace period for consumers to be updated to the new version of the protocol.

[Ostrzyciel]

code looks good :)