Feature/vote 636/state field mail link

[SamiraMSadat]

Jira ticket

https://cm-jira.usa.gov/browse/VOTE-636

Description

Added a state mail-in link to the state fields, and to the NVRF API.

Deployment and testing

Pre-deploy

1. lando retune

QA/Test

1. View the edit page of a state content page and confirm there is a field for "mail registration link" and "mail registration link override" in the Links tab
2. Go to the NVRF API confirm the mail registration link and override (hidden) are in the fields list.

Checklist for the Developer

• A link to the JIRA ticket has been included above.
• No merge conflicts exist with the target branch.
• Automated tests have passed on this PR.
• A reviewer has been designated.
• Deployment and testing steps have been documented above, if applicable.

Checklist for the Peer Reviewers

• The file changes are relevant to the task objective.
• Code is readable and includes appropriate commenting.
• Code standards and best practices are followed.
• QA/Test steps were successfully completed, if applicable.
• Applicable logs are free of errors.

[rayestrada]

Approved!