A previous commit implemented a streamlined performance metric reporting
system for the compiler-cli, controlled via the compiler option
`tracePerformance`.

This commit adds a custom Bazel flag rule //packages/compiler-cli:ng_perf
to the repository, and wires it through to the `ng_module` implementation
such that if the flag is set, `ng_module` will produce perf results as part
of the build. The underlying mechanism of `//:ng_perf` is not exported from
`@angular/bazel` as a public rule that consumers can use, so there is little
risk of accidental dependency on the contents of these perf traces.

An alias is added so that `--ng_perf` is a Bazel flag which works in our
repository.

PR Close #41125