App Check Framework

[kc-diabeat]

It would be nice to have a set of checks for validating app's codebase. The checks can be triggered while running zelthy3 commands and they can also be shown as alerts on the App Panel.

Few relevant checks that I can think:

• module name having invalid characters
• model subclassing models.Model instead of DynamicModelBase
• Unsupported field type used (e.g. ManyToManyField in v0.1)
• registered module not found
• validation failure for settings.json
• validation failure for manifest.json
• necessary services unreachable - e.g. redis, celery ,etc.

In future, we can also consider including syntactical as well as logical checks on the App's codebase (e.g. syntax error in a view) in the framework.