Reimplement RecruitmentCycle::CYCLE

[inulty-dfe]

Context

• Make it a module method
• The single positional argument sets the limit on the labels generated

Changes proposed in this pull request

Reimplement the RecruitmentCycle constant CYCLE as a module method. avoids the need to manually add a new recruitment cycle each year.

Guidance to review

Is there a specific period during the Recruitment Cycle when the next years cycle should appear?

Link to Trello card

Things to check

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