Use `RSpec.#{method}` for top level DSLs
e.g.
 * use RSpec.describe as opposed to describe
 * use RSpec DSL for shared examples
Configure whether to expose DSL globally
top level dsl under RSpec
describe behaviour with/without global namespace DSL
monkey patching must be explicity enabled if using same file *breaking change*
supress warning
expose globally true/false
spec out isolated expose globally on/off
describe at runtime configuration of global exposure
configure ignores for method cache prevention
remove toplevel check for exposure (its also checked in the two DSL exposure)
move config default to only usage