Changes to properly support Mutexes on NET6.0

[conradmicallef]

Global Mutexes were being created without insufficient rights for a 2nd process running on same machine to use them

This fix addresses that by using same methodology applied to NETFRAMEWORK but to NET6.0

[inbarbarkai]

Is there any plan on merging this PR?

[tjmoore]

Any update? What's the symptom without this fix, is there a particular error raised?

Looking for solutions to access denied errors on shared mode access, but I'm not seeing it on the mutex but on the journal file (and only one process is writing, the other opens database in read mode).