Mutable `fee-recipient-addresses`

[OisinKyne]

🎯 Problem to be solved

We want to modify fee recipient addresses of unallocated keys. Ideally we don't want to restart our cluster or experience any down time.

🛠️ Proposed solution

Describe the solution to be implemented. TBD on an internal doc.

(Ideas:

• Persist updates on disk in .charon if they supercede the lockfile, just load them in and start using them.
• Submit them to a running charon's vAPI (from another charon fee-recipient update command, making our first client/daemon type UX
• Support some sort of distribution of this ask? the ux of an edit command?

🧪 Tests

• Tested by new automated unit/integration/smoke tests
• Manually tested on core team/canary/test clusters
• Manually tested on local compose simnet