[1549] generate models controllers routes and basic templates for provider and national reports

[elceebee]

Context

We are replacing the ‘mid-cycle report’ with a weekly-generated RecruitmentPerformanceReport. There will be both a national and provider level report.

Changes proposed in this pull request

Note: the migration is in a separate PR. Once that is merged in, I'll rebase this and the migration files will disappear from this PR]

This PR is for implementing the

• basic scaffolding (models, controllers, views, specs) for the report.
• Feature flag to hide the functionality

More detail will be in the next PRs (eg, actual views with data, better data in the factories, seed data, link from the Reports page)

Guidance to review

• Either locally, or in the review app, sign in as a support user and activate the recruitment_performance_report feature flag
• Visit publications/recruitment-performance-report
• Sign in as a provider user and visit the /provider/reports/:provider_id/recruitment-performance-report

Link to Trello card

https://trello.com/c/wHhTrLWl

Things to check

• [x] If the code removes any existing feature flags, a data migration has also been added to delete the entry from the database
• [x] This code does not rely on migrations in the same Pull Request
• [x] If this code includes a migration adding or changing columns, it also backfills existing records for consistency
• [x] If this code adds a column to the DB, decide whether it needs to be in analytics yml file or analytics blocklist
• [x] API release notes have been updated if necessary
• [x] If it adds a significant user-facing change, is it documented in the CHANGELOG?
• [x] Required environment variables have been updated added to the Azure KeyVault

[elceebee]

Generate models, controllers, routes and basic templates for Provider and National Reports