Remove proxy as optional feature

[thunderbiscuit]

Potentially fixes #91.

I wanted to take a stab at this but I'm not sure I really understood why proxy was a feature in the first place. Was there a reason to have it turned off that we want to preserve, in which case we might need to address this by changing the feature-gating done on the Client type?

Anyway just opening this to see if it passes the whole CI workflow.

[tnull]

Potentially fixes #91.

I wanted to take a stab at this but I'm not sure I really understood why proxy was a feature in the first place. Was there a reason to have it turned off that we want to preserve, in which case we might need to address this by changing the feature-gating done on the Client type?

Anyway just opening this to see if it passes the whole CI workflow.

FWIW, it would be great to be able to disable the optional dependencies. However, as it stands, the proxy feature doesn't really seem to be fully optional. The only difference it makes is that users that only want to use api::ElectrumApi, but not the actual client would be able to disable the additional proxy dependencies. Then again, if that's the only use-case, it should probably be called client, not proxy, as it's mandatory for client use currently.