added pages theme code to /docs on repo on git.soton otherwise the mirror to...

added pages theme code to /docs on repo on git.soton otherwise the mirror to github over-writes it. NO CONTENT changed on github is preserved when we mirror OUT from git.soton

docs/_config.yml

+theme: jekyll-theme-time-machine
\ No newline at end of file

[Ben Anderson]

See https://docs.gitlab.com/ee/user/project/repository/repository_mirroring.html#pushing-to-a-remote-repository-core for more on gitlab mirroring