Run Lighthouse checks during CI

[deweydell]

Description

We want to monitor that changes to the website do not negatively affect our SEO, performance, accessibility, or progressive web app features.

Because Lighthouse GH integration only works with Travis CI, this issue is dependent on #14.

Acceptance Criteria

• Lighthouse check is run on a branch when a PR is opened
• Results of lighthouse check are posted in a comment or in the commit checks

Resources

https://github.com/GoogleChromeLabs/lighthousebot

[halfghaninne]

I'm interested in working on this issue! Plan to work on this the week of 5/6

[halfghaninne]

@deweydell - Lighthouse set up requires us to add a bot as a contributor to our repo! I don't believe I have the permissions to do so on this repository.

[halfghaninne]

Update 5/18: Continue to remain blocked, but now with a new blocker! Please see PR #47 for details.