Improve integratio test coverage

[Jiaxiao Zhou]

We will need to improve our integration test coverage on a few other popular use cases of slight and spin shims.

• Test a workload that uses more than one spin components, better if they are written in different langauges
• Test a workload that uses spin's outbound redis, pg, http capability
• Test the slight chat-app workload

[Jiaxiao Zhou]

#65