EPIC: Cache Warmup

[s2b]

One major goal for Fluid 5 is to implement a (mostly) context-free possibility to warmup the cache of Fluid templates. Most of the road blocks are related to the caching mechanism depending on data only present during runtime/rendering of a template. Some of those have already been addressed by introducing deprecations in Fluid 4:

• [TASK] Deprecate ViewHelper namespace inheritance #1080
• [TASK] Establish proper API to set template layout #1090

However, there are still some ToDos left:

• rethink naming of cache files (partial, layout, template as prefixes; action and controller name)
• refactor TemplatePaths API to get rid of controllerName and actionName in favor of something more reasonable, like templateName
• refactor/deprecate existing warmup feature, which needs too much context at the moment to be used in most use cases
• create new cache warmup command

One context information will still be necessary: The defined global ViewHelper namespaces. The reason is that both ViewHelper class names and the newly introduced ViewHelperResolver delegates are currently resolved during parse time and baked in to the cache files.