Solution: add a warning message and remove jobs with invalid tasks

[dannielb]

Hello!

Proposal:

At Quantum startup, when detected that a mfa task is not a valid function, ignore the job configuration and show a warning message.

closes #507

[coveralls]

Pull Request Test Coverage Report for Build 22b8db2346aa33f619f4e69853f27e7439236e89-PR-523

• 14 of 14 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.8%) to 86.486%

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Totals
Change from base Build ac74242ad0f26db2970d6c122c3b90b64b64381d:	0.8%
Covered Lines:	352
Relevant Lines:	407

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💛 - Coveralls