Rewording for new rules and eligibility criteria

[lukeocodes]

Description

I've been through the site based on the latest rule changes and updated the participation details and rules. I could not test changes the airtable information for the FAQ, so I have left those changes out.

Test process

• [x] Run in dev (w/ Docker)
• [x] Load the homepage - see the text has changed
• [x] Load the details page - see the text has changed
• [x] Run tests
• [x] Run the pull-request spec test specifically

Requirements to merge

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code in hard-to-understand areas
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes

[MarkCBell]

Although this PR addressed almost all of the new rule changes, it missed changing one reference to the "seven-day review window". I have opened #639 to address this.