Issue 80 automate testing

[jerneyio]

This PR addresses issue https://github.com/nokia/kong-oidc/issues/80. It's a bit hard to see the changes since I've moved some files around so here's a synopsis:

• README.md - Added testing instructions to the end. Removed CI instructions.
• test/docker/integration/docker-compose.yml - Externalized a lot of the properties and removed the command
• test/docker/integration/setup.py - added validate_ip_set and get_env_vars methods. Added env parameter to get_config file. get_config now works by using much of the same properties in the .env file at the root of the project. Modified classes to include more parameters. Added print functions to give user insight into what it is doing
• test/unit/run.sh - loop through test/unit/test_*.lua files and run all of them instead of listing them explicitly.

Any suggestions welcomed.

[coveralls]

Pull Request Test Coverage Report for Build 108

• 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 96.0%

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Totals
Change from base Build 102:	0.0%
Covered Lines:	120
Relevant Lines:	125

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💛 - Coveralls

[Trojan295]

Overall I like this. Easy and works great. Add only those shebangs to bash scripts and I'll merge it.