Move plugin communication handler init out of plugin manager init

[ASpoonPlaysGames]

Plugin state requires this to be initialised even if -noplugins is passed, but if -noplugins is passed, it doesn't get initialised.

Moving this to dllmain guarantees that it is initialised properly and prevents #580

closes #580

[Jan200101]

Tested and it works without a hitch.

Code is clean and moves the global init into the InitNS function, like many other things are.

[GeckoEidechse]

Merging based on reviews.