Previously, we were using ngx-build-plus with a custom webpack config to determine the git SHA at runtime.
Now, after migrating to bazel and transfering to angular/angular, this commit uses ng-dev to stamp the latest git SHA directly in angular devtools' application environment.
This commit also removes the old webpack configs.
Previously we were running Cypress with bazel in an effort to save on CI time when devtools dependencies did not change. This commit reverts to running Cypress manually, until we can revisit building devtools with local Angular packages to save CI time.
