* Add relevant files from private repo

Hopefully I didn't miss anything.

JsonHelper.cs is a debug only change
I only added line 810-812 in IUserLocalCommunicationService.cs
for the new Spacemeowx2Ldn case.

* Add a small README.md

just for fun

* Add note about NetCoreServer update to 5.1.0

* Fix a few issues

Fix usage of wrong broadcast address
Log warning if empty userstring was received
and don't add them to outNetworkInfo

* Add warning about incompatibility with public LDN version

* Add missing changes from old_master

* Adjust ldn_mitm for Ryujinx/Ryujinx#3805

* ldn: Adapt to changes from #4582

* ldn_mitm: First cleanup iteration

* ldn_mitm: Second cleanup iteration

* Credit spacemeowx2 in README.md

* Address first review comments by AcK

Adhere to Ryujinx coding style
Remove leftover log calls
Change category of a few log calls
Remove leftover debug notes

* Replace return type with void for methods...