Previously, camel case was used for bazel labels in the devtools directory. This commit changes these labels to snake case except in the case where the label is identical to the directory name that the BUILD file is in.
Both of these comments were included accidentally after porting over bazel code from angular/angular and angular/components to devtools.
They are not relevant to devtools so this commit removes them.
Removes MDC constants and unneeded angular package configs from packages.bzl.
Removes partial-compilation-integration from the karma web test tags because we don't perform any of partial compilation integration tests for devtools.
Some tooling was brought in from angular/components to help with bundling spec files for Karma. This tooling has since been ported over to the dev-infra repo. This commit dedupes the tooling and instead depends on the angular/dev-infra-private repo.
