Run AWS Lambda tests locally

[antonpirker]

Test Sentry AWS Lambda integration locally instead of creating actual Lambda function in AWS:

• Create a local AWS Lambda environment using AWS SAM and AWS CDK. (Docker based)
• Start a local Sentry server that accepts envelopes.
• Run the tests in the local AWS Lambda environment configured with a DSN that tells the SDK to send data to the local Sentry server.
• Read the captured envelopes from the local Sentry server to assert their correctness.
• Update CI configuration, so AWS tests are now handled the same as test suite matrices of other integrations.

There is also a follow-up PR that removes obsolete code handling AWS authentication data: #4076 (This PR will also fix the one failing test)

Fixes #2795

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.55%. Comparing base (a97c53c) to head (a858cdb).
Report is 1 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3988      +/-   ##
==========================================
+ Coverage   79.53%   79.55%   +0.01%     
==========================================
  Files         140      140              
  Lines       15594    15594              
  Branches     2647     2647              
==========================================
+ Hits        12403    12406       +3     
- Misses       2351     2355       +4     
+ Partials      840      833       -7     

see 5 files with indirect coverage changes

[sentrivana]

Overall looking great. I tried comparing the old tests to the new ones and it seems to me like we might not be testing the following anymore:

• sampling context being correct (old test name was test_traces_sampler_gets_correct_values_in_sampling_context)
• different behavior if perf is enabled/disabled (tests ending in ..._performance_enabled/disabled)

Maybe this is included in the new tests, it's just hard to diff 😇