feat(prover): flag for proving unassigned proofs or not

[cyberhorsey]

this pr adds a flag to the prover, which can determien whether this prover should prove unasigned proofs or not.

unassigned proofs:

1. one where the proofWindow expires and the assignedprover did not submit a proof on time
2. one where the protocol was out of capacity, and the assignedprover is address(0), which means anyone can submit proof.

This can be useful because if you are proving an unassigned proof, and you get assigned a proof, you will not start generating it until the expired proof is done if you are at proving capacity, and you may potentially be slashed if you are late delivering the proof. So you may want to configure two provers on two different machines, one set to true, one set to false, to ensure you have a prover always working on your assigned proofs.

Also improves logging in these areas which was lacking.

[codecov]

Codecov Report

Merging #314 (7d8d3c3) into main (b0b4c25) will increase coverage by 0.01%.
The diff coverage is 6.25%.

@@            Coverage Diff             @@
##             main     #314      +/-   ##
==========================================
+ Coverage   50.86%   50.88%   +0.01%     
==========================================
  Files          36       36              
  Lines        3910     3950      +40     
==========================================
+ Hits         1989     2010      +21     
- Misses       1666     1683      +17     
- Partials      255      257       +2     

Impacted Files	Coverage Δ
prover/prover.go	43.01% <4.25%> (+1.22%)	⬆️
prover/config.go	72.00% <100.00%> (+0.37%)	⬆️

... and 1 file with indirect coverage changes

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