Optimizing detection of active menu_items
cache_enabled setting with the initializer
First cache implementation for show_menu

We extracted some of the previous optimization logic to some methods
conditional_cache_menu for the others menu helpers
Migration for storing when a menu item is really a leaf
Setting the leaf flag when saving a menu item
Testing that changes in children affects parents leaf flag
Optimizing leaf_with_draft detection
Adding a scope for finding leaves with drafts
Using the new leaves scope in the menus helper
Translating leaf with drafts as it depends on draft attributes that are translated
Using the new translated version of leaf with drafts
Merge branch 'features/helpers-optimization'
Menu items now need some menu