Remove legacy tracing

[sentrivana]

Remove the Transaction and Span and NoOpSpan classes (likely the whole tracing.py file). Remove legacy tracing functions and attributes from scope.py. Rename streamed versions of functions in scope.py (start_streamed_span → start_span, etc.). Remove any options, constants, etc. only used in transaction-based tracing (e.g. max span limits, etc.).

[linear-code]

PY-2655

[mgaligniana]

Hi @sentrivana! I was about to start working on #6975 to take the opportunity to get familiar with the tests but I think starting with this will make the rest of the work easier because it will end up removing a lot of code/tests. Unless an employee has already been assigned*

[sentrivana]

Hey @mgaligniana, thanks for checking in! 👋🏻 The issue you're referencing (reducing test suite size) is already assigned to someone from the team and it's being worked on.

This issue is part of a larger project to remove legacy tracing in the next major. We track the project off GitHub unfortunately so that link is missing here. It'll need to be done systematically because it's going to be a huge change, so this is also not a good candidate to pick up.

[mgaligniana]

Perfect, no problem! Thank you!!