refactor grails-encoder packages
move org.grails.web.util.* and org.grails.web.pages.* in grails-encoder to org.grails.buffer
move taglib parts from grails-web-gsp to grails-web-taglib and output encoding parts to grails-web-encoder
- the goal is to refactor taglib and output encoding solution (XSS prevention) in to a standalone module so that taglibs can be used without GSPs in other template engines in Grails (and Spring Boot)
- leave GSP syntax tags in grails-web-gsp, but move to new package or.grails.web.pages.tags since syntax tags are specific to GSPs
- delete RenderInputTag which has been deprecated