Goal:

• Syncing templates from git should use a HTTP proxy when a default HTTP proxy is set in settings to allow Satellites running in IPV6-only environments to sync templates from IPV4-only accessible git servers

Acceptance Criteria:

Open questions:

• Q: allow selecting proxies in sync form?
  A: allow selecting from a list of already created proxies, allow to unset
• Q: the state of http proxies in automation is unknown
• Q: docs side of things
• A: rn, no change to the actual template syncing procedure
• Q: hammer?
  A: yes. Changes to api and hammer should automatically propagate to the relevant guides, we'd like to avoid explicitly adding a single step procedure to the product guides
• Q: permissions?
  A: always should the one from settings, the ones from infrastructure > http proxies only subject to permissions, might have docs impact

QE Automation Tracker for https://issues.redhat.com/browse/SAT-27349