Feat/mock mining hot swap

[ASuciuX]

Fixes #4705

I went through all the hot-swappable fields and wrote this to follow the architecture implemented for burnchain hot-swappable fields from the config.

How I tested this using clarinet for devnet and regtest nodes:

Moved my testing commits to this external branch .

1. Have my updated code + the 2 commits from Hugo.
2. Build a custom docker image using the last commit from this source branch using this commit 214ae48c0a2c2bac6cd593039210cc21ac3e5e0b.
3. Custom clarinet devnet start:
   a. Use the built docker image for stacks_node_image_url = "localhost:5001/stacks-node:mock-miner"
   b. Disable automatically bitcoin mining to check balances bitcoin_controller_automining_disabled = true. This is performed as we expect the stacks-mock-miner not to spend bitcoin, while the stacks-miner spends for mining.
4. Get into stacks-node docker container > files > src>stacks-node>Stacks.toml and add mock_mining=true.
5. Results on the image below - when the mock-miner was true, there were no stacks-blocks created, in that frame 4 bitcoin blocks were mined and 0 stacks blocks. After switching back the config to not have mock-miner, it mined stacks blocks again.

[ASuciuX]

I'm removing the extra code about clarinet, but want to keep the commit history for this to still be checked/tested. The only commit for the mock-mining hot-swappable is 4245554ae0863f0e5afa802266bca1b697b29bd8.

[obycode]

LGTM!