Update Jenkins plugins: 2020Q1 → 2020Q2 edition

Updating those that have CVEs is already covered by sysadmin shifts. This is about updating all plugins as we can’t rely on every security issue to get a CVE and there’s no LTS with security support.

This includes giving a crash course to groente + zen so they know how to do that.

Related issues

Blocks #13284
Blocked by #10068 (closed)

Original created by @intrigeri on 16955 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information