Create archive of custom build of InterMine

Running `intermine_boot build local` will build and archive an InterMine instance, saving the archives to `intermine_boot` in `XDG_DATA_HOME` (use a search engine to find out which folder this is on your operating system).

Currently, only archives for `postgres`, `solr` and `biotestmine` are created. In the case where the user has specified the flag `--build-im` (optionally along with `--im-repo` or `--im-branch`), we should also create an archive for `intermine`. This is built in the `intermine_builder` container (https://github.com/intermine/docker-intermine-gradle/blob/a631235c95e5407d9ba928504217c276e319a1d7/intermine_builder/build.sh#L12).

Gradle will install these files to `~/.m2` inside the intermine_builder docker container, so I think archiving this folder will be enough. You will probably need to add a docker volume for this.

Note that this issue will require PRs to this repo, as well as https://github.com/intermine/docker-intermine-gradle.

You can start working on this issue immediately without waiting to be assigned (but please add a comment), even if someone has commented before you. We've decided to not assign issues and allow anyone interested to submit a PR. Obviously we won't be able to merge all the PRs, so don't worry about being first. All PRs whether merged or not, will be part of our evaluation of an intern.

It would also be great if you could explain your approach and rationale in the PR description. This only needs to be as long or as in depth as you feel it needs to be for the specific task.