Fixes T5752. This obsoletes a bunch of old patterns and I'll follow up on those with a big "go do a bunch of mechanical code changes" task. Major goals are:
- Don't load named queries multiple times on search pages.
- Don't require extra code to get standard navigation right on mobile.
- Reduce the amount of boilerplate in ListControllers.
- Reduce the amount of boilerplate around navigation/menus in all controllers.
Specifically, here's what this does:
- The StandardPage is now a smarter/more structured object with setNavigation() and setCrumbs() methods. More rendering decisions are delayed until the last possible moment.
- It uses this to automatically add crumb actions to the application menu.
- It uses this to automatically reuse one SearchEngine instead of running queries multiple times.
- The new preferred way to build responses is $this->newPage() (like $this->newDialog()), which has structured methods for adding stuff (setTitle(), etc).
- SearchEngine exposes a new convenience method so you don't have to do all the controller delegation stuff.
- Building menus is generally simpler.