Support Groovy Markup templating in Spring MVC

Solution #1

This commit adds support for Groovy templating, available as of
Groovy 2.3.0 (and 2.3.1 for advanced use cases, such as layouts and
fragments).

To enable this, one should create a new GroovyMarkupViewResolver
Bean in their application context.

Issue: SPR-11789
Support Groovy Markup templating in Spring MVC

Solution #2

This commit adds support for Groovy templating, available as of
Groovy 2.3.0 (and 2.3.1 for advanced use cases, such as layouts and
fragments).

To enable this, one should create a new GroovyMarkupViewResolver
and a new GroovyMarkupConfigurer Beans in their application context.

Issue: SPR-11789