feat(jobsdb): introduce partition_id column

[atzoum]

Description

JobsDB tables now have a new column, partition_id.
This column will be indexed and populated in the following JobsDB instances:

• gw
• rt
• batch_rt

The value for partition_id is computed as {{workspaceID}}-{{murmur3Hash32Index(userID)}}, meaning:

• The first part comes from the job’s WorkspaceID
• The second part is the partition index derived from the job’s UserID

Note: Existing jobs in the database will have an empty partition_id. This is acceptable, as the column will not be actively used for some time.

Linear Ticket

Resolves PIPE-2557
Resolves PIPE-2559

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 is 87.50000% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.30%. Comparing base (56dc15e) to head (af40a64).

Files with missing lines	Patch %	Lines
jobsdb/jobsdb.go	88.37%	3 Missing and 2 partials ⚠️
app/apphandlers/processorAppHandler.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6502      +/-   ##
==========================================
- Coverage   79.41%   79.30%   -0.11%     
==========================================
  Files         531      531              
  Lines       59739    59786      +47     
==========================================
- Hits        47439    47412      -27     
- Misses       9455     9536      +81     
+ Partials     2845     2838       -7     

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