v3.0.0-rc.3 UI Refresh

Merged fixes from hotfix-3-0-0-rc-2:

• fixes PushHttpProxy for updated react/http (#401)

• fixes #407 narrow layout zinger

• fixes #409 whitespace in recent reviews category filter

• closes #403 add share playlist link

• closes #402 add classic search filter

• implements Slack integration (#408)

• refactors album details to Twig (#406)

• migrates recent reviews to twig; changes default sort order to date desc

• updates airname reassignment to account for vaultkeeper duplicates

• fixes new user account to lock direct login if no password supplied

• updates ZootopiaListener to deal with stale show_end