chore: Refactor Captures to use Contexts

[kamilprz]

Description

Refactoring the capture manager and capture commands to create a context hierarchy by passing it around, rather than creating a new one in each method with context.TODO.

Related Issue

#317

Checklist

• I have read the contributing documentation.
• I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• I have correctly attributed the author(s) of the code.
• I have tested the changes locally.
• I have followed the project's style guidelines.
• I have updated the documentation, if necessary.
• I have added tests, if applicable.

Additional Notes

https://go.dev/blog/context

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[kamilprz]

@timraymond @alexcastilio please take a look and point out mistakes or ways to make things better :)

Also in terms of testing, make test succeeds with 0 failures - do we deem that enough of a validation that things are ok? I'm not entirely sure how to validate scenarios where the context is cancelled? Would it just be running a capture and terminating with Ctrl+C?

[timraymond]

Looks great! One quick suggestion, but nothing blocking.