feat(tracing): support combined EventFilters and EventMappings

[lcian]

It seems common enough that someone would want to want to map a tracing event to multiple item types, and right now that's not possible, you have to choose between Ignore/Event/Breadcrumb/Log.
For example, in Relay we want to send everything at or above INFO level to logs, while still sending ERROR events to Sentry events at the same time.

This is a proposal for how to implement that.
This particular solution requires 2 breaking changes, even though both could be avoided.
I would argue that they are not actually breaking for most users though, i.e. those that just set up a custom filter, as this is still backwards compatible in terms of syntax, even though the underlying type changes.

[github-actions]

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📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 07dd2c7

[codecov]

Codecov Report

Attention: Patch coverage is 90.47619% with 4 lines in your changes missing coverage. Please review.

Project coverage is 74.21%. Comparing base (333b14e) to head (07dd2c7).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #847      +/-   ##
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+ Coverage   74.05%   74.21%   +0.16%     
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  Files          64       64              
  Lines        7781     7807      +26     
==========================================
+ Hits         5762     5794      +32     
+ Misses       2019     2013       -6     

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