Adds parameter for security classification

[wpfl-dbt]

Context

REDBOX-294. Just as we allow many different LLMs to be used, different departments will permit different levels of security assurance on documents staff are permitted to use with Redbox. This ticket is to add an environment variable to allow the frontend to make changes based on an app-wide setting.

Changes proposed in this pull request

• Add MAX_SECURITY_CLASSIFICATION
• Add places for Django to pick it up and display it

Guidance to review

• Checked my overall strategy with @KevinEtchells but make sure you're happy with how I pass that env around
• In particular, I use case switch because I think an extension of this kind of work would involve quite a few different settings that result from the max security level of documents permitted

Relevant links

• Government Security Classifications

Things to check

• I have added any new ENV vars in all deployed environments
• I have tested any code added or changed
• I have run integration tests

[brunns]

Suggest using an enum, but it's up to you.

[brunns]

We could make this an enum:

class Classification(enum.StrEnum):
    OFFICIAL = "Official"
    OFFICIAL_SENSITIVE = "Official Sensitive"
    ...
    
MAX_SECURITY_CLASSIFICATION = Classification[env.str("MAX_SECURITY_CLASSIFICATION")]

We'd need to use underscores rather than dashes in the names for them, of course.

[brunns]

Also - would we want a default value?

[252afh]

I'm fine withw/without an enum. r.e. default, we want it to fall over if they haven't set it

[wpfl-dbt]

Thought about it and decided to use the enum.

[brunns]

If we were to use an enum, we'd want MAX_SECURITY_CLASSIFICATION.value.

[brunns]

Looks good!