Add support for connecting to resource using IPv6

[JonnyWong16]

Description

Add support for connecting to resource using IPv6.

The default behaviour is to try all IPv4 and IPv6 connection URIs (ipv6=None), with IPv4 preferred first (DEFAULT_IP_ORDER = ['ipv4', 'ipv6']). Set the parameter ipv6=True to only connect to IPv6 and ipv6=False to only connect to IPv4.

from plexapi.myplex import MyPlexAccount

account = MyPlexAccount(token="XXXXXXXXXX")
plex = account.resource("My Server").connect(ipv6=True)

Ref.: https://forums.plex.tv/t/plex-media-server/30447/708

• (Network) IPv6 support has TEMPORARILY been made a plex pass feature (PM-5140)
• (Network) Support for ipv6 only networks (PM-5140)

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the docstring for new or existing methods
• I have added tests when applicable