Optimize types config files auto discover configuration

[mcg-web]

Q	A
Bug fix?	yes
New feature?	yes
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Documented?	yes
Fixed tickets	#192
License	MIT

• Add ability to disabled/enabled types config files auto discover from root dir config and bundles config

overblog_graphql:
   definitions:
       mappings:
           # disabling all auto discover
           auto_discover: false
           # or to disable just bundles
           #auto_discover:
           #    bundles: false
           #    root_dir: true

• Add suffix to override default types file suffix

overblog_graphql:
   definitions:
       mappings:
           types:
               -
                   type: yaml # or xml or null
                   dir: "%kernel.root_dir%/.../mapping"
                   suffix: _types