Adds __map__ functionality

[ncilfone]

What does this PR do?

Adds map functionality as another post instantiation hook option. This allows you to directly map spock configs to object creation etc. automatically upon creation. Additional docs and tests

Checklist

• Did you adhere to PEP-8 standards?
• Did you run black and isort prior to submitting your PR?
• Does your PR pass all existing unit tests?
• Did you add associated unit tests for any additional functionality?
• Did you provide code documentation (Google Docstring format) whenever possible, even for simple functions or classes?
• Did you add necessary documentation to the website?

[ncilfone]

Merged in fix for #296 - fixed tests to remove the r+w check since default is now changed to not check privs

[ncilfone]

@mmalouane This is the new PR that will cover #296 as well. Can you review and merge and release to help unblock this: #297 (comment)

[coveralls]

Pull Request Test Coverage Report for Build 6746688429

• 57 of 57 (100.0%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 99.379%

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Totals
Change from base Build 6746625954:	0.006%
Covered Lines:	3520
Relevant Lines:	3542

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💛 - Coveralls

[ncilfone]

@mmalouane Ignore the failing build on 3.6 since we are deprecating support -- I think that one is stuck somehow. You should be able to force the merge as along as all the other tests pass