Move building and testing from Travis to GitHub Workflow

[garrettjstevens]

@elliothershberg and I worked on this together. This removes .travis.yml and moves the testing and build steps to two new workflows that run on every push:

• test
  • runs tests
  • uploads coverage
  • checks typescript types
• build
  • builds codebase
  • runs build-only tests
  • uploads branch build to S3 in the same location Travis did

So far the build step takes the longest at right around 20 minutes, and we haven't seen any builds time out.

Fixes #1328

[cmdcolin]

wow, big win! sad to see travis go but this looks much better if the stability holds

[elliothershberg]

Yeah I think getting down to ~20 min from ~35 will be really nice

[elliothershberg]

If we switch to GH Actions, it looks like they have their own API for badges: docs

Would look like this:

So maybe worth renaming from Push to Build? If we want to keep using shields.io with the same style it would look something like this:

[![Build Status](https://img.shields.io/github/workflow/status/GMOD/jbrowse-components/Push/master?logo=github&style=for-the-badge)]()

(example using this branch instead of master), but I'm not sure what the the URL would be to link to results of the action.

We could do something like:

https://github.com/GMOD/jbrowse-components/actions?query=workflow%3APush+branch%3Amaster+

which would link to the results of Push (or Build) for master