Refactor and Document check_env.check()

[bmos]

What is this change?

• Add comprehensive documentation to check_env.check().
• Do not allow optional to be treated as a positional parameter.
• Rename field parameter to value for clarity, with deprecation warning for old parameter name.
• Adjust a few nonstandard imports of check directly rather than via importing check_env.

Considerations for discussion

• Despite being a core function used in many connectors, check_env.check() was minimally documented.
• Allowing users to provide boolean values for positional parameters is not recommended as their intention can be confusing.

How to test the changes (if needed)

• CI tests should be adequate

Breaking Changes

Breaking changes are changes to our public API which may require existing users to change their code. If there are no breaking changes, any existing parsons user should not need to do anything after updating their parsons version.

Does this PR introduce breaking changes?

• label: Breaking change — This PR introduces one or more breaking changes.
• label: Non-breaking change — This PR does not introduce one or more breaking changes.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
parsons/aws
lambda_distribute.py					205
parsons/notifications
slack.py					128
parsons/redash
redash.py
parsons/utilities
check_env.py					39-44
Project Total

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[bmos]

Do we consider these breaking changes?
I think this function is only used within connectors?