New role: Plex meta manager

[jolbol1]

Description

Plex meta manager: https://github.com/meisnate12/Plex-Meta-Manager

Please include a summary of the change and which issue is fixed if any. Please also include relevant motivation and context. List any dependencies that are required for this change.

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• [x] Running on my server. Ubuntu 18.04 headless with cloudbox
• [x] Ran on test server with fresh install.

New Role Checklist:

• [x] I have reviewed the Contribute page in the wiki
• [x] I have updated the header in any files I may have used as templates with my own information
• [x] I have added my new role to appveyor.yml
• [x] I have added my new role to community.yml
• [x] I have verified that any Docker images used are current and supported.
• [ ] I have made corresponding changes to the documentation