Prevent redeploys.

Causes a ton of test failures; surprise surprise.
Move validation into ev/record-deploy.
Split validation into its own function.

Record-deploy needs the file to be written already so it can index and checksum.
Only insert DB row on pom deploy.
Remove unused require
Any valid push to a group shoud claim it
Add a test to ensure redeploying over existing artifacts is blocked.
Merge branch 'no-redeploy'

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Clarify that redeploying snapshots is OK.
Bump a few deps.
Revert "Update hiccup / safe-hiccup"

This reverts commit eaf1e897f839742a37a20a2c62eac66075c57a15.

Will revisit this once we determine why it's causing test failures.
Release 0.14.0.