fix: only handle the Queue Announcements either by Core or CFBG, not both

[FrancescoBorzi]

• Closes #58

I believe the current system is wrong as it lets both the CFBG and the core handle announcements. Instead, it should be only one of them. This was resulting in bugs such as #58

Now I changed it to:

• only make the Core handle the queue announcements IF it is arena OR if the CFBG is disabled
• only make the CFBG handle the queue announcements otherwise

Test performed:

• tested locally with 1 player and the bug #58 is gone
• tested both withCFBG.Enable = 1 and CFBG.Enable = 0, both seems fine

What needs to be tested:

• test BG queue announcer in general, possibly with more chars ( both withCFBG.Enable = 1 and CFBG.Enable = 0)
• a quick check on arena queue announcements wouldn't be bad, so we make sure we don't break them ( both withCFBG.Enable = 1 and CFBG.Enable = 0)
• check that there is no regression in the queue announcements, it would be nice a quick check the Limit feature recently added
• would be interesting to play with Battleground.QueueAnnouncer.SpamProtection.Delay too and see how it goes

[FrancescoBorzi]

cc @Winfidonarleyan @Sedatyf