[APPSEC-56188] Replace Scope with Context

[Strech]

What does this PR do?

Replace irresponsible class AppSec::Scope with AppSec::Context and move some functionality into it.

Motivation:

In order to implement RASP/WAF telemetry and metrics we need to adjust the domain of the AppSec. The main point - AppSec::Context represents request context and hides complexity of the security engine calls (and gathering statistics) from the instrumentation.

You will see some obvious issues with existing code because of that change, but that's the plan. We move slowly with a guaranteed compatibility.

Change log entry

No.

Additional Notes:

This is the first PR which establishes the base to develop metrics collection. In this PR introduces as minimum as possible changes to stay compatible, but move forward.

How to test the change?

CI (specifically systems tests) should be enough.

[datadog-datadog-prod-us1]

Datadog Report

Branch report: appsec-56188-replace-scope-with-context
Commit report: 92b6443
Test service: dd-trace-rb

✅ 0 Failed, 22187 Passed, 1477 Skipped, 5m 23.48s Total Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-13 11:20:12

Comparing candidate commit 92b6443 in PR branch appsec-56188-replace-scope-with-context with baseline commit c856145 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 31 metrics, 2 unstable metrics.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 99.71014% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.72%. Comparing base (c856145) to head (92b6443).

Files with missing lines	Patch %	Lines
.../datadog/appsec/contrib/graphql/gateway/watcher.rb	85.71%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4277   +/-   ##
=======================================
  Coverage   97.72%   97.72%           
=======================================
  Files        1354     1354           
  Lines       82421    82415    -6     
  Branches     4220     4220           
=======================================
- Hits        80543    80539    -4     
+ Misses       1878     1876    -2     

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