chore(jobsdb): unify get processed and unprocessed queries

[atzoum]

Description

By unifying getUnprocessed and getProcessed under a single getJobs method which is able to handle both processed and unprocessed job states with a single database query, we can execute less queries, which translates to lower overall query times and finally less jobsdb locks:

• router now executes a single GetToProcess query instead of 3 (GetToRetry, GetWaiting, GetUnprocessed)
• batchrouter now executes a single GetToProcess query instead of 2 (GetToRetry, GetUnprocessed)
• stash now executes a single GetToProcess query instead of 2 (GetToRetry, GetUnprocessed)

Other changes:

• Rename jobsdb.GetQueryParamsT to jobsdb.GetQueryParams
• Rename jobsdb.HandleT to jobsdb.Handle
• Using generics for achieving type safe dbRequests

Monitoring dashboard adaptations

After this change has been rolled out, we need to unify the following JobsDB panels in Grafana under a single Get Jobs Stats panel:

• Processed Fetch Stats
• Unprocessed Fetch Stats Time

Linear Ticket

Link

Security

• The code changed/added as part of this pull request won't create any security issues with how the software is being used.

[codecov]

Codecov Report

Patch coverage: 84.63% and project coverage change: -0.27% ⚠️

Comparison is base (188b95c) 68.80% compared to head (d80f4ce) 68.54%.
Report is 1 commits behind head on master.

❗ Current head d80f4ce differs from pull request most recent head db33a50. Consider uploading reports for the commit db33a50 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3742      +/-   ##
==========================================
- Coverage   68.80%   68.54%   -0.27%     
==========================================
  Files         344      344              
  Lines       51936    51259     -677     
==========================================
- Hits        35736    35136     -600     
+ Misses      13896    13854      -42     
+ Partials     2304     2269      -35     

Files Changed	Coverage Δ
app/apphandlers/embeddedAppHandler.go	75.95% <0.00%> (-0.73%)	⬇️
app/apphandlers/processorAppHandler.go	9.32% <0.00%> (+0.76%)	⬆️
enterprise/replay/dumpsloader.go	0.00% <0.00%> (ø)
enterprise/replay/replay.go	0.00% <0.00%> (ø)
enterprise/replay/setup.go	0.00% <0.00%> (ø)
processor/manager.go	90.00% <ø> (-0.17%)	⬇️
router/batchrouter/handle_async.go	0.00% <0.00%> (ø)
router/batchrouter/handle.go	62.91% <83.33%> (-0.30%)	⬇️
jobsdb/jobsdb.go	72.50% <89.63%> (+0.03%)	⬆️
jobsdb/backup.go	69.25% <91.66%> (-0.34%)	⬇️
... and 13 more

... and 38 files with indirect coverage changes

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