Adding serializers, tests, and minor refactoring

[gsa-jrothacker]

Purpose

This small PR adds the serializers which will allow the saving/creating of Audits (next PR). There is also some minor refactoring.

Testing

local linting, end to end tests

Notes

A lot of this work was done by @rnovak338

[github-actions]

Terraform plan for meta

No changes. Your infrastructure matches the configuration.

No changes. Your infrastructure matches the configuration.

Terraform has compared your real infrastructure against your configuration
and found no differences, so no changes are needed.

📝 Plan generated in Pull Request Checks #4423

[github-actions]

Terraform plan for dev

Plan: 1 to add, 0 to change, 1 to destroy.

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

  # module.dev.module.cors.null_resource.cors_header must be replaced
-/+ resource "null_resource" "cors_header" {
!~      id       = "*******************" -> (known after apply)
!~      triggers = { # forces replacement
!~          "always_run" = "2025-02-28T17:31:23Z" -> (known after apply)
        }
    }

Plan: 1 to add, 0 to change, 1 to destroy.

📝 Plan generated in Pull Request Checks #4423

[github-actions]

This pull request is not up to date with main. Please merge main into this brach or rebase this branch onto main. This PR should not be approved until all status checks pass. If you see this message, please rerun all status checks before merging.

[github-actions]

Package	Line Rate	Branch Rate	Health
.	100%	100%	✔
api	98%	90%	✔
audit	97%	87%	✔
audit.cross_validation	98%	88%	✔
audit.fixtures	84%	50%	❌
audit.intakelib	88%	82%	➖
audit.intakelib.checks	92%	85%	➖
audit.intakelib.common	98%	82%	✔
audit.intakelib.transforms	100%	95%	✔
audit.management.commands	78%	17%	❌
audit.migrations	100%	100%	✔
audit.models	94%	73%	➖
audit.templatetags	100%	100%	✔
audit.views	72%	54%	❌
census_historical_migration	96%	65%	✔
census_historical_migration.migrations	100%	100%	✔
census_historical_migration.sac_general_lib	92%	84%	➖
census_historical_migration.transforms	95%	90%	✔
census_historical_migration.workbooklib	68%	69%	❌
config	77%	37%	❌
curation	100%	100%	✔
curation.curationlib	93%	100%	➖
curation.migrations	100%	100%	✔
dissemination	92%	72%	➖
dissemination.migrations	97%	25%	✔
dissemination.searchlib	76%	66%	❌
dissemination.templatetags	100%	100%	✔
djangooidc	53%	38%	❌
djangooidc.tests	100%	94%	✔
report_submission	93%	88%	➖
report_submission.migrations	100%	100%	✔
report_submission.templatetags	74%	100%	❌
support	91%	66%	➖
support.migrations	100%	100%	✔
support.models	96%	50%	✔
tools	98%	50%	✔
users	95%	92%	➖
users.fixtures	100%	83%	✔
users.management	100%	100%	✔
users.management.commands	100%	100%	✔
users.migrations	100%	100%	✔
Summary	91% (18503 / 20270)	77% (2277 / 2962)	➖