Add support for reasoning about server semantic version

[bdpedigo]

Note: Currently, this is just for the chunkedgraph, but could easily be extended to the other services if we like the pattern

This PR adds

• Adds logic for talking to an endpoint which just returns the full semver for the service
  • Happens on sub-client creation
• Stores this info as a Version object, which allows for easy operations like checking >,>= etc.
• Adds a decorator for convenience, which allows specification that a method or its keyword arguments are only valid for specific constraints of server version
  • Opted not to do that for arguments, could discuss further but since those are required that felt like it didn't fit the pattern
• As an example, applies this decorator to a recent addition to the level2_chunk_graph bounds argument

This PR does not add

A few things we discussed but I think are separate PRs

• In theory, this kind of reasoning about the server version might allow for consolidating the multiple API version clients into one for each service, with method-level logic about dispatching to particular sub-functions depending on the version
• There are some use cases that don't fall under the decorator that are more adhoc, for instance, the recent bug where using timestamp and select columns can be unsafe. I think those will need to be done on a case by case basis, but could at least use some of the tools here

Worth discussing

• How to generalize testing with this kind of thing (since mocking needs to happen @ client level)
• How to handle case for servers that don't have this endpoint yet (I have some ideas here but it gets ugly)
  • How to refactor to use handle_response but be OK with a 404 error