storagemgr: Cleanup workerLk around worker resources

[magik6k]

Mostly just untangling some tech debt to make it easier to add better smarts around starting work.

[codecov]

Codecov Report

Merging #7334 (ef03314) into master (aab42dd) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #7334      +/-   ##
==========================================
- Coverage   39.14%   39.11%   -0.03%     
==========================================
  Files         614      614              
  Lines       64997    64995       -2     
==========================================
- Hits        25440    25422      -18     
- Misses      35143    35159      +16     
  Partials     4414     4414              

Impacted Files	Coverage Δ
extern/sector-storage/sched.go	84.71% <ø> (ø)
extern/sector-storage/sched_worker.go	78.38% <100.00%> (-0.32%)	⬇️
extern/sector-storage/stats.go	60.34% <100.00%> (+1.41%)	⬆️
markets/loggers/loggers.go	89.28% <0.00%> (-10.72%)	⬇️
chain/events/observer.go	71.64% <0.00%> (-6.72%)	⬇️
chain/stmgr/execute.go	86.95% <0.00%> (-4.35%)	⬇️
chain/exchange/peer_tracker.go	66.66% <0.00%> (-4.31%)	⬇️
chain/exchange/client.go	49.15% <0.00%> (-3.82%)	⬇️
node/hello/hello.go	63.63% <0.00%> (-3.41%)	⬇️
chain/store/store.go	63.31% <0.00%> (-1.77%)	⬇️
... and 15 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update aab42dd...ef03314. Read the comment docs.