doc: install and update

[glensc]

please add doc how to install and enable this plugin.

and also how do you create release and publish this.

as i looked into my kodi directory and noticed you have .git/ folder included in release. and also that i have only version 0.0.8 installed, even there are new releases in github. so seems auto update procedure is not present/enabled.

~/.kodi/addons/plugin.video.kanal2.ee # du -s .git
424K    .git
~/.kodi/addons/plugin.video.kanal2.ee # git describe --tags
v0.0.8
~/.kodi/addons/plugin.video.kanal2.ee #