show date on most posts and clean up display of admin panel

[itsthejoker]

Relevant issue: N/a

Description:

Adds the date to posts that aren't in the menu bar (like the donation page / about page) and also trades out the boolean field in the admin panel for ✓ / ✗ instead of True / False.

Screenshots:

Post detail view:

Index view:

Note that header bar posts are unaffected:

Admin panel change:

Checklist:

• [x] Code Quality
• [x] Pep-8
• [ ] Tests (if applicable)
• [x] Success Criteria Met
• [x] Inline Documentation
• [ ] Wiki Documentation (if applicable)