Add fields for tracking where jobs are executed

[bjester]

Summary

Adds new fields to the jobs table which allow us to better reconcile the jobs with their status if worker execution is interrupted for some reason. These fields track:

• the hostname of the worker
• the process ID of the worker
• the thread ID of the worker
• any extra data the worker wants to track

References

Closes #9710

Reviewer guidance

There should be no perceptible change. The extra fields can be observed in the database, e.g.:

$ sqlite3 job_storage.sqlite3 
SQLite version 3.37.2 2022-01-06 13:25:41
Enter ".help" for usage hints.

sqlite> select id, func, state, worker_host, worker_process, worker_thread from jobs;
id                                func                                                          state      worker_host  worker_process  worker_thread  
--------------------------------  ------------------------------------------------------------  ---------  -----------  --------------  ---------------
d10e8b82fc8340a09dc886b53a841a46  kolibri.core.content.tasks.automatic_resource_import          COMPLETED  phlack       51781           140127435208256
1                                 kolibri.core.deviceadmin.tasks.perform_vacuum                 QUEUED     NULL         NULL            NULL           
streamed_cache_cleanup            kolibri.core.deviceadmin.tasks.streamed_cache_cleanup         QUEUED     NULL         NULL            NULL           
1000                              kolibri.core.discovery.tasks.reset_connection_states          QUEUED     phlack       51781           140127435208256
935d0c9cbb2ed6d2b971b26c6a3a2314  kolibri.core.discovery.tasks.add_dynamic_network_location     COMPLETED  phlack       51781           140127435208256
178d445f96e4ef5c8239edffc7e3472c  kolibri.core.discovery.tasks.perform_network_location_update  COMPLETED  phlack       51781           140127435208256
50                                kolibri.core.auth.tasks.soud_sync_processing                  QUEUED     phlack       51781           140127435208256
f870bab4a1884593bfc918f8d421ec1b  kolibri.core.auth.tasks.cleanupsync                           COMPLETED  phlack       51781           140120455886400
d660db3c63b846eebaad9bfd71bdc175  kolibri.core.content.tasks.automatic_resource_import          FAILED     phlack       51781           140120455886400
2dc8e34f08234f3bbdba42a6bd4bd48c  kolibri.core.auth.tasks.cleanupsync                           COMPLETED  phlack       51781           140127435208256
e38dd2e4c1f2456cb9aa94b7476dbb7d  kolibri.core.content.tasks.automatic_resource_import          FAILED     phlack       51781           140127435208256
0740f4d6436348a382a2dd5048b3c678  kolibri.core.auth.tasks.cleanupsync                           COMPLETED  phlack       51781           140120455886400
191b720c94c3410d980970d26eb85726  kolibri.core.content.tasks.automatic_resource_import          FAILED     phlack       51781           140120455886400

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Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.16.0b9.dev0_git.61.ga8ac8be0.pex
Windows Installer (EXE)	kolibri-0.16.0b9.dev0+git.61.ga8ac8be0-unsigned.exe
Debian Package	kolibri_0.16.0b9.dev0+git.61.ga8ac8be0-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.16.0b9.dev0+git.61.ga8ac8be0-0.3.0.dmg
Android Package (APK)	kolibri-0.16.0b9.dev0+git.61.ga8ac8be0-0.1.0-debug.apk
TAR file	kolibri-0.16.0b9.dev0+git.61.ga8ac8be0.tar.gz
WHL file	kolibri-0.16.0b9.dev0+git.61.ga8ac8be0-py2.py3-none-any.whl

[rtibbles]

Works as expected!