Add syncnets data to Altair MetaData

[ralexstokes]

Fixes #2347.

[pawanjay176]

This would also add a v2 version for GetMetaData response in rpc right?

[djrtwo]

This would also add a v2 version for GetMetaData response in rpc right?

Yes, I think that's the simplest way to handle the content changes on the MetaData type here.

We'd probably also want to specify that this new GetMetaData version can be enabled at anytime prior to the fork

[ralexstokes]

Added the "get metadata v2" req/resp endpoint -- the guide already discusses upgrading to v2 ahead of the fork so it seems that has already been covered

[djrtwo]

excellent. thank you!