Add integration test setup and examples folder

[skovhus]

#68

When fixing a caching issue in the promotion of images, I decided to wrap up some old integrations tests I started on a while ago. Manually testing Brick is very tedious, so a few high level integrations tests really helps here.

We are testing on a fairly high level:

• asserting which docker images was found on the system
• asserting which docker images was built (based on the log for now)
• asserting which docker images were promoted (based on the logs for now)
• a few additional asserts on the log output from Brick

We test several scenarios here:

• build a single workspace on master
• rebuilt a single workspace on master (caching)
• rebuilt a single workspace on a new branch (promoting)
• building a workspace
• testing a workspace

[corradio]

I'll let @madsnedergaard review if that's fine with you.
Thanks for cc'ing me though!

[madsnedergaard]

LGTM!

[madsnedergaard]

Started reviewing yesterday, but thought I was hitting an infinite loop when running the test since my CPU was going crazy for so long - turns out it just need more time 😄

[skovhus]

Started reviewing yesterday, but thought I was hitting an infinite loop when running the test since my CPU was going crazy for so long - turns out it just need more time 😄

Wow! They take 40 seconds on CI... Wondering if something else was wrong 🤔