Expose the rest of the RPC methods inside the SDK

[chefsale]

Context RPC methods dir: https://github.com/calimero-network/core/tree/master/crates/server/src/admin/handlers/context

Not all methods are exposed via the SDK, like context creation and joining, but all others should be available as well. This is needed to be able to be able to create automatic invites and joining from the client.

cc: @MatejVukosav @xilosada