Update `plans/build-base-plans` to support "path/to/plan:name" syntax.
Update `plans/build-base-plans` to support "path/to/plan:name" syntax.

This change allows plans under `components/` to be built, even if their
directory name does not match the package name.

habitat-sh/habitat,nathenharvey/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,nathenharvey/habitat,rsertelon/habitat,rsertelon/habitat,georgemarshall/habitat,nathenharvey/habitat,nathenharvey/habitat,habitat-sh/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,nathenharvey/habitat,habitat-sh/habitat,habitat-sh/habitat,georgemarshall/habitat,georgemarshall/habitat,rsertelon/habitat