## Issue being fixed or feature implemented
Dashmate wanted a way to know if it is safe to restart the masternode.
This new RPC indicates the number of active DKG sessions, and the number
of blocks until next potential DKG.
## What was done?
Examples of responses:
`{'active_dkgs': 0, 'next_dkg': 22}`
## How Has This Been Tested?
`feature_llmq_rotation.py` was updated
## Breaking Changes
no
## Checklist:
- [x] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [x] I have added or updated relevant unit/integration/functional/e2e
tests
- [x] I have made corresponding changes to the documentation
- [x] I have assigned this pull request to a milestone _(for repository
code-owners and collaborators only)_
---------
Co-authored-by: UdjinM6 <UdjinM6@users.noreply.github.com>
