[python + travisCI] Automatically deploy and generate documentation

HTML documentation for our library can be generated using the `pydoc -w` command.

It would be nice to use [travis](https://docs.travis-ci.com/user/deployment/pages/) or github actions to automatically generate docs and deploy them to the gh-pages branch of this repo.

This should only happen for the master branch.

## if you want to pick up this task

0. Take a look at the [InterMine contributing guidelines](http://intermine.org/contributing/)
1. Comment on this issue stating that you intend to work on the task
2. When you're ready, add your work to the repo and create a pull request.
### What to do if you need help

Mention @yochannah, tweet [@yoyehudi](http://www.twitter.com/yoyehudi), pop by to say hi on [chat](http://chat.intermine.org) or if needed email yo@intermine.org. Don't forget we're usually only available during uk office hours and will not be able to respond at other times :)