Umbrella: Improve memory usage and caching of forms

[ebruchez]

This is an umbrella bug. Related bugs:

• Session heartbeat doesn't work as intended #2013: Session heartbeat doesn't work as intended
• Issue with cache eviction from other thread #1989: Issue with cache eviction from other thread
• Heartbeat per form session #2014: Heartbeat per form session
• Sessions time out sooner than session-timeout setting unpredictably #1596: Sessions time out sooner than session-timeout setting unpredictably
• Expire entries from disk store #1990: Expire entries from disk store
• Improved XForms document cache sized in bytes #1973: Improved XForms document cache sized in bytes
• Make static state cache weaker #1572: Make static state cache weaker
• There can be more than one copy of the static state in memory #1991: There can be more than one copy of the static state in memory
• Support XForms instance whitespace stripping #1339: Support XForms inline instance whitespace stripping
• FB: Publish should strip whitespace from form definition #1715: Publish should strip whitespace from form definition
• XForms: static state must not depend on dom4j #2128: XForms: static state must not depend on dom4j
• More optimal static representation of forms #1204: More optimal static representation of forms
• Too many duplicate strings #1605: Too many duplicate strings
• Improve caching to reduce delay between request and XForms processing #1239: Improve caching to reduce delay between request and XForms processing
• For #1143: Complete noscript mode caching changes #1712: For FR: new/edit/view/pdf modes must use same cached form definition #1143: Complete noscript mode caching changes
• Schema mode should use same cacheable form definition #1731: Schema mode should use same cacheable form definition
• FB: Test mode must not use cache entries when possible #1730: FB: Test mode must not use cache entries
• Passivate XFCD state upon FR navigation or asynchronously #1815: Passivate XFCD state upon FR navigation or asynchronously
• Form Runner admin console with analytics #1946: Form Runner admin/performance console
• Caching of form definition is influenced by document id #1681: Caching of form definition is influenced by document id
• FR: new/edit/view/pdf modes must use same cached form definition #1143: FR: new/edit/view/pdf modes must use same cached form definition
• Review XForms cache architecture #1718: Review XForms cache architecture