Refactoring of observation related activities

[hellais]

• Add support for performing observation generation using multiple cores, instead of multiple threads since it's CPU bound
• Separate observation activities into distinct smaller activities allowing for more narrowly scoped scheduling and retry policies
• Change the type of PrevRange so that it's possible to serialize it in JSON allowing to pass it as a parameter to activities
• Move update_assets into observation activity
• Add support for passing config file via CONFIG_FILE environment variable
• Improvements to the CLI commands
• Drop several CLI arguments that should only be read from the config file
• Other improvements related to typing

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 86.62551% with 65 lines in your changes missing coverage. Please review.

Project coverage is 81.63%. Comparing base (f17863b) to head (38f61e1). Report is 1 commits behind head on v5.0.0-rc.0.

Files with missing lines	Patch %	Lines
...onipipeline/src/oonipipeline/temporal/schedules.py	82.50%	14 Missing :warning:
...ine/src/oonipipeline/temporal/client_operations.py	28.57%	10 Missing :warning:
oonipipeline/src/oonipipeline/cli/commands.py	57.14%	9 Missing :warning:
...c/oonipipeline/temporal/activities/observations.py	91.75%	8 Missing :warning:
oonipipeline/src/oonipipeline/temporal/workers.py	50.00%	7 Missing :warning:
...peline/src/oonipipeline/temporal/workflows/ctrl.py	78.26%	5 Missing :warning:
...ine/src/oonipipeline/temporal/activities/common.py	75.00%	4 Missing :warning:
...line/src/oonipipeline/temporal/workflows/common.py	72.72%	3 Missing :warning:
.../oonipipeline/temporal/activities/ground_truths.py	66.66%	1 Missing :warning:
oonipipeline/src/oonipipeline/temporal/common.py	94.73%	1 Missing :warning:
... and 3 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v5.0.0-rc.0 #86 +/- ## =============================================== + Coverage 77.41% 81.63% +4.21% =============================================== Files 32 82 +50 Lines 1913 6339 +4426 =============================================== + Hits 1481 5175 +3694 - Misses 432 1164 +732 ``` | [Flag](https://app.codecov.io/gh/ooni/data/pull/86/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ooni) | Coverage Δ | | |---|---|---| | [oonidata](https://app.codecov.io/gh/ooni/data/pull/86/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ooni) | `77.44% <100.00%> (+0.02%)` | :arrow_up: | | [oonipipeline](https://app.codecov.io/gh/ooni/data/pull/86/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ooni) | `83.45% <86.54%> (?)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ooni#carryforward-flags-in-the-pull-request-comment) to find out more.

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