Align on facet variable naming convention

[nathanielw44]

Overview

• Align on common naming convention for facet group vs facet dict vs facet name instead of just calling blanket calling everything "facet" and getting confused.
• Rename a bunch of variables to be more explicit about what type they actually are

# A "facet group" is a list of facet dicts that are all applied together with an AND or OR type 
facet_group = {
	'type': 'or',
	'facets': [
		{'key': 'feature_needed', 'value': '' },
		{'key': 'feature_needed', 'value': 'metric' },
		...
	]
}

# a facet dict is one of the key value pairs that a of data object can match 
facet_dict = {'key': 'feature_needed', 'value': 'metric' }

# The "key" of a facet dict is a "facet_name"
facet_name = 'feature_needed'

How to test

• Let's see if the build passes
• Naming changes make the code more clear and easier to read than before

[coveralls]

Pull Request Test Coverage Report for Build 12033921404

Details

• 63 of 63 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.008%) to 92.446%

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Totals
Change from base Build 7672290461:	0.008%
Covered Lines:	820
Relevant Lines:	887

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💛 - Coveralls

[nathanielw44]

@anthonyp97 This is the bug you fixed you fixed in #38 - comparing facet_names with facet dicts. Decided to leave it alone for now because fixing it breaks a ton of tests, so I think it warrants its own PR