Add ability to split master when only 1 additional window (#2025)

* fix: enable master split less than 2 windows

added a config flag  "master:allow_small_split"
added config to minimum windows check.
TODO: check that no bug added (remove all masters?)

* IMPL:FIX: multiple master windows full width

Implemented the ability to have multiple master windows filling the full
monitor width in master mode.
this is controlled by the config option master:allow_small_split
(true/false)
this defaults to false as it was the original behaviour before this
patch

* BUGFIX: corrected issue with blanks re: addmaster

FIX 1: Treat ORIENTATION_CENTER the same as ORIENTATION_LEFT unless
there are enough STACK_WINDOWS to fill both wings.
FIX 2: enforced last window always set as master in
MasterLayout::CHyperMasterLayout::calculateWorkspace();
FIX 3: fix 2, also fixed focus issues previously noted.

* Changes requested by vaxerski

changed how we access config variables (by reference not value)
fixed a regression previously missed prior to requested changes.
I had somehow broken the very functionality i meant to add.

* added static keyword to config variables

* removed superfluous static tags

I made a mistake with making too many variables static.
this made them only evaluate once per runtime breaking things majorly.
My appologies. I haven't touched C++ in nearly 20 years.

* remove annoying comment

---------

Co-authored-by: vaxerski <43317083+vaxerski@users.noreply.github.com>

src/config/ConfigManager.cpp

@@ -144,6 +144,7 @@ void CConfigManager::setDefaultVars() {
     configValues["master:no_gaps_when_only"].intValue      = 0;
     configValues["master:orientation"].strValue            = "left";
     configValues["master:inherit_fullscreen"].intValue     = 1;
+    configValues["master:allow_small_split"].intValue      = 0;
 
     configValues["animations:enabled"].intValue = 1;