Add basic test infrastructure

Create initial test which pushes and starts the test web application
and checks it is started.

Read test application configuration from its manifest.yml. Add random
string to subdomain, but not to application name.

Support MySQL services.

[#59676046]
Documentation

[#59676046]
Improve test infrastructure

[#59676046]
Merge 59676046-test-infrastructure to master

[Completes #59676046]