[Feature]: Initiating distributed key generation

[djordon]

Feature - Initiating distributed key generation

1. Description

The signers cannot do anything without aggregate key, so we need to specify some conditions that will trigger all signer to initiate distributed key generation (DKG) at the same time.

1.1 Context & Purpose

Although we have much of the logic for completing DKG, we do not have any of the logic for initiating it. Right now we just need to support initiating DKG from some hard configured block height (either stacks or bitcoin) and/ via an endpoint that is only available in a testing mode.

2. Technical Details:

2.1 Acceptance Criteria:

• There is an endpoint in the signer binary that can kick off DGK.
• There is a config variable that will trigger DKG if the signer notices that the signers as a group don't have an aggregate key and the current block height is greater than the configured minimum block height for DKG.

3. Related Issues and Pull Requests (optional):

[djordon]

The first part, triggering DKG from an HTTP request, we shouldn't do. A modified version of the second part, configuring DKG from some config variable, was done in #1200.