Support for getting a schema from a portal (C4-1089)

[netsettler]

• Add misc_utils.to_camelcase.
• Add qa_utils.is_subdict.
• Add ff_utils.get_schema and ff_utils.get_schemas (C4-1089).
• Add unit tests for bug C4-1087 (marked xfail).

Other opportunistic changes:

• Minor tweaks to ff_utils.dump_results_to_json for style reasons, and repairs to its overly complex and error-prone unit test.
• Various tiny grammar changes comments and doc strings while I was in there in ff_utils because PyCharm grammar checker was fussing.

NOTES TO REVIEWERS:

• I am not sure why this endpoint is called profiles and not schemas, or what the difference is. So @willronchetti had originally suggested some sort of get_profile function for ff_utils but I decided to call it get_schema instead since that better describes what I want. If there is a reason get_profile is a better name, that would be useful to know.
• Will had suggested a single function to get either a single schema or several, but that complicates the return type in the type hints, so I opted for separate functions to keep the simple function returning something that doesn't have to be peeled down further upon receipt. I don't really even need get_schemas so am open to a suggestion to just not include that, though I can see why it might be useful. It would be more useful if the profile operation took (maybe comma-separated?) several filenames.

[coveralls]

Pull Request Test Coverage Report for Build 5943374735

• 72 of 74 (97.3%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 77.745%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
dcicutils/ff_utils.py	23	24	95.83%
dcicutils/qa_utils.py	45	46	97.83%
<!--	Total:	72	74	97.3%	-->

Totals
Change from base Build 5894343897:	0.2%
Covered Lines:	8234
Relevant Lines:	10591

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💛 - Coveralls