chore(build): rename subprojects.gradle to .settings.gradle

This makes it clearer that these are applied to the settings script, not
the build script.

settings.gradle

@@ -8,7 +8,7 @@ include 'engine', 'engine-tests', 'facades', 'metas', 'libs', 'modules'
 rootDir.eachDir { possibleSubprojectDir ->
 
     // First scan through all subdirs that has a subprojects.gradle in it and apply that script (recursive search!)
-    possibleSubprojectDir.eachFileMatch FileType.FILES, ~/subprojects\.gradle/, { subprojectsSpecificationScript ->
+    possibleSubprojectDir.eachFileMatch FileType.FILES, ~/subprojects\.settings\.gradle/, { subprojectsSpecificationScript ->
         //println "Magic is happening, applying from " + subprojectsSpecificationScript
         apply from: subprojectsSpecificationScript
     }