[Feature]: Coordinator attempts second DKG after a block height

[djordon]

Feature - Coordinator attempts second DKG after a block height

1. Description

The second DKG run will be gated by our bitcoin clock. That is, we will not run DKG again until after the arrival of a given bitcoin block with a specific height. This height will be a required configurable value set in the signers config, since we need to support this in multiple environments. After the arrival of the block at the configured height, the coordinator should attempt to run DKG.

With the current codebase the second DKG run will fail, but that is fine. We will fix that as part of a separate issue.

1.1 Context & Purpose

We want to support running key rotation. Full key rotation is quite complicated, so we are breaking it out into small and simple phases. We've already done phase 0, which is support running DKG once. The second phase is to run DKG a second time. This second DKG will be gated by bitcoin time.

2. Technical Details:

We need to add a config variable and modify the coordinator to try to run DKG if

1. DKG has never been run, or
2. DKG has been run exactly once and the current block height is greater the configured bitcoin block height.

2.1 Acceptance Criteria:

• The coordinator will attempt to run DKG a second time if the current block height is greater than the configured block height.
• The coordinator wall still run DKG once if it has never been run before.

3. Related Issues and Pull Requests (optional):