[ENG-4907] Add moderation message to OSF Preprints

[futa-ikeda]

Purpose

• Add info text about our moderation policy to users submitting to OSF Preprints

Summary of Changes/Side Effects

• Add translation text
• show text if users are submitting to OSF Preprints
• On the preprints/submit page:
  

Testing Notes

• OSF Preprints should have its reviews_workflow changed to post-moderation in the admin app
• Message "You can read more about OSF Preprints moderation policies..." should only show up for users submitting to OSF Preprints
  • Help link currently goes to a "Page not found", but will be made public upon release.
• Message should show/hide when users select OSF Preprints or a different provider in the "Select a service" panel in preprints/submit page. The message won't update until "Save and continue" is pressed

Ticket

https://openscience.atlassian.net/browse/ENG-4907

Notes for Reviewer

Reviewer Checklist

• meets requirements
• easy to understand
• DRY
• testable and includes test(s)
• changes described in CHANGELOG.md

[coveralls]

coverage: 23.882%. remained the same
when pulling af09d2a on futa-ikeda:osf-preprints-mod-message
into 3ecdb81 on CenterForOpenScience:develop.