Parallelize some timer work

[Porges]

When we update distinct entities we can perform the updates in parallel. Do this in TimerTasks and TimerWorkers.

[codecov-commenter]

Codecov Report

Merging #3600 (54a0680) into main (957f1fb) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3600      +/-   ##
==========================================
- Coverage   39.97%   39.97%   -0.01%     
==========================================
  Files         303      303              
  Lines       37698    37703       +5     
  Branches     1725     1718       -7     
==========================================
- Hits        15071    15070       -1     
- Misses      22305    22312       +7     
+ Partials      322      321       -1     

Files	Coverage Δ
.../ApiService/ApiService/onefuzzlib/JobOperations.cs	10.00% <0.00%> (ø)
src/ApiService/ApiService/Functions/TimerTasks.cs	0.00% <0.00%> (ø)
...ApiService/ApiService/onefuzzlib/NodeOperations.cs	16.77% <0.00%> (-0.11%)	⬇️
...rc/ApiService/ApiService/Functions/TimerWorkers.cs	0.00% <0.00%> (ø)

... and 2 files with indirect coverage changes