Automate docs tests with bats

[dutradda]

Bats is a bash tests suite / runner. https://github.com/sstephenson/bats

The docs tests are written in bash script, but there is no test suite yet.

Acceptance Criteria:

• The tests must use the coverage command to run the uvicorn server.
• The bats must be included on Makefile.
• The coverage must be combined with the unit tests.