Choices are not constraints... for Sal developers

[sheagcraig]

Describe the bug
We have a number of choices arguments for models in Sal. This prevents users from inputting invalid values from forms... Unfortunately, the code itself can happily set values that are not one of the choices. This creates a situation where the DB may have values it was never meant to, and client code may blow up.

To Reproduce

1. Check in a device and use the operatingsystem "AcornOS" or perhaps "Debian".
2. Watch the operatingsystem plugin thrash.

Expected behavior
In most cases we probably want to reject invalid values.

[sheagcraig]

https://adamj.eu/tech/2020/01/22/djangos-field-choices-dont-constrain-your-data/