Cache webpack loaders in CI

What does this MR do?

Add babel-loader and vue-loader cache directories in CI .assets-compile-cache. This would shorten the duration of gitlab:assets:compile * and compile-assets *.

Both babel-loader and vue-loader are configured to cache the results of the loader, however, these are not cached in CI.

• https://gitlab.com/gitlab-org/gitlab/blob/master/config/webpack.config.js#L170
• https://gitlab.com/gitlab-org/gitlab/blob/master/config/webpack.config.js#L177

Improvement on webpack:compile:

job	before	after
gitlab:assets:compile *	https://gitlab.com/gitlab-org/gitlab/-/jobs/387084112 858.251527153 seconds	https://gitlab.com/gitlab-org/gitlab/-/jobs/387141231 799.6164218 seconds
compile-assets *	https://gitlab.com/gitlab-org/gitlab/-/jobs/387084101 126.851373365 seconds	https://gitlab.com/gitlab-org/gitlab/-/jobs/387141222 84.85300992 seconds

Part of #34319 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Merge request performance guidelines