The internal Maven mode almost never works, and we do not really use it. Icsuggest we just remove this mode from PCT entirely.

Old TODO comment: "most plugin tests fail to build using internal Maven; PlexusWagonProvider.lookup with a roleHint=https fails for no clear reason, and some missing {{SNAPSHOT}}s cause a build failure related to https://github.com/stapler/stapler-adjunct-codemirror/commit/da995b03a1f165fef7c9d34eadb15797f58399cd

"