Added configuration for commonmark use in twig-extra-bundle.

[doekenorg]

Following this tweet: https://twitter.com/ramsey/status/1561894460560138241, this PR adds the configuration options for commonmark to the twig-extra-bundle.

The configuration is added to the LeagueCommonMarkConverterFactory and in turn injected in the CommonMarkConverter. This way a user can provide the configuration for usage inside twig.

I'm not sure if adding the configuration inside the extension is the way to go.

Hope this helps out at least @ramsey :-)

Added ignoreExtraKeys to be somewhat future proof in case extra configuration is added later on, and also to be able to provide de configuration for extensions.