ideas for extending the patch YAML system

[beckermr]

Here are some ideas for extending the patch YAML system:

• enable logical negation for the if conditions (i.e., the Python equivalent of not ...) (ENH enable negation #510)
• enable an outer list if syntax where the inner items are dicts (entries are combined via AND) and the outer list items are combined via OR. (can use another template instead)
• add a required comment field in the pydantic model so that we can keep the reasons for the patches machine-readable
• add a debug field per-patch that would output info as the patch is applied/tested to help people figure out why a patch was not working (this would need to have its own set of conditions so that it didn't print gobs of text)
• add input data that could be referenced
• support referencing current record values via string.Template with $ syntax. (ENH allow template strings #513)
• add support for has_constrains in if section (ENH support has constrains #512)

cc @jaimergp