Enable RabbitMQ when testing with tox

[sajith]

Resolves #244.

There were errors when running tox with RabbitMQ enabled via tox-docker. It turned out that we actually need to wait for RabbitMQ to be ready, which can be done by adding some health checks.

[coveralls]

Pull Request Test Coverage Report for Build 8286426205

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 38.63%

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Totals
Change from base Build 8160653207:	0.0%
Covered Lines:	619
Relevant Lines:	1442

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💛 - Coveralls