Description

We need a Rendered Title Cache for performance reasons.

This is probably costing us a lot ATM, for example if you're in a 10 level hierarchy, you load 10 docs in memory.

Design ideas:

• Start by transforming the Docuement Title metadata from a String into a TextArea
• One line displayed by default but expand to more when pressing enter in the title field
• Switch title content to wiki content. Thus any script will need to use a scripting Macro. This provides the ability to use a scripting language other than Velocity. It also allows to recognize titles that are dynamic vs static titles.
• If title contains a Macro then make the title non cacheable, i.e. still add an entry in the title cache but with a flag that says it's non cacheable. When the cache is asked for this title it'll get it from the document and not from some cached value.
• Have a table in the DB for caching rendered titles and when a doc is modified, update it (similar strategy than backlinks). This would allow LiveTables to filter and sort titles. 
• When a title is dynamic (ie macros in title), don't display the rendered content in liveTables, etc. Instead, display only the page name in this case. This allows to handle cases when the current logged in user doesn't have permissions to execute some part of the title.