Allow configuring ignore paths and ingore patterns for autodiscovery

[ryancausey]

Is your feature request related to a problem? Please describe.
I have found an interesting issue when combining prospector with GitLab CI caching. The CI caching has the requirement that the directories and files to cache must be within the project's root directory. This leads to a .cache folder ending up inside the project's directory during CI/CD runs. Something in this folder is currently causing prospector to autodetect that I am using Django when I am not. I tried to apply ignore paths and ignore patterns to this problem, but it had no effect. Upon inspection of the code, I can see that the autodiscovery is invoked upon construction of the ProspectorConfig object, but none of the CLI arguments go on to affect autodiscovery.

Describe the solution you'd like
I'd like to be able to configure autodiscovery to ignore this directory. It is probably best to have separate configuration options so as to not introduce weird interactions with existing usage of ignore paths and ignore patterns.

Describe alternatives you've considered
I can disable autodiscovery.