Add a dedicated Plex Media Server per section

[KyleSanderson]

Help yourself

• I did try to restart Kodi :-)
• I checked the PKC Frequently Asked Questions on the PKC wiki
• I did try to reset the Kodi database by going to PKC Settings -> Advanced -> "Reset the database and optionally reset PlexKodiConnect" and then hitting YES, NO
• I did check the existing issues on Github

Describe the bug

The product is pretty darn close, with varying replacements per type available in the addon. The single last thing that's missing is to specify a Plex Server per section. This aligns with the "namespaces" that are in the addon, the logical breakout that xbmc has always had, and servers for each type.