refactor: remove connection protocol

[dbluhm]

This PR Removes the deprecated connections protocol.

In addition to the message handlers and routes, this also means:

• CLI flags relating to connections protocol removed.
• References to specific messages in base connection manager were removed; there will need to be some working around this in the plugin to continue to support the protocol but I think it's good and necessary to at least rip it out for now here.
• Introduction protocol used to use Connections invitations. I did a very rough-and-ready conversion to OOB invites.
• Connections management routes (e.g. querying connections) were moved to aries_cloudagent.connections.routes (from aries_cloudagent.protocols.connections.v1_0.routes).

I am expecting this to not be fully functional yet so opening as a draft for now.

[PatStLouis]

@dbluhm it was mentioned on the call this was moved to a plugin. Is the code to enable using that plugin included in this pr?

[swcurran]

It’s in the plugin repo: hyperledger/aries-acapy-plugins#925

[PatStLouis]

@swcurran thank you, I was referring towards the "code required to make this plugin work" which was highlighted in the meeting.

The functionality lost/broken features outlined here, will this require code from within the aca-py code base or it can all be managed in the external plugin?

[swcurran]

Doh…sorry about that. Good point. And per my comment in the meeting — is it viable to simply document how to use the plugin? I suppose not being able to use the artifacts directly (e.g., having to change the Python code) might be a bit too painful.

[dbluhm]

With the most recent updates on this branch and to the corresponding plugin, I have successfully completed a connection using the plugged in connection protocol. There are some failing tests I will address but I will go ahead and mark this as ready for review.

[sonarcloud]

Quality Gate failed

Failed conditions
52.8% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud