This moves out the checks that get run in GHA CI into ci/gha/tests
folder and splits those into `topLevel` and `componentTests` attributes.
The idea behind this is to make it easier to parametrize tests that can
be run with sanitizers in order to run those as a matrix of jobs. The same
can be said for static builds.
Existing stdenv selection infrastructure via `lib.makeComponents` would
also allow us to switch over to using `clangStdenv` to significantly speed
up pre-merge CI (though the default stdenv would still be used for non-overridable
topLevel checks, like installer artifacts).
This adds a GHA jobs to help analyze build times
and its regressions. It is based on `clangStdenv` with `-ftime-trace`
together with `ClangBuildAnalyzer` to prepare markdown summary for
individual components.
This also has the minor benefit of dogfooding CA and impure derivations.
