Search Kit builder UX improvements

Following discussion at the sprint with @gibsonoliver, @davem, @colemanw, @christhompson, @callanpaterson {please add others} – am aggregating some of the feedback.

What this isn't. A proposal for a UX rewrite, which would normally start with a whole process of user feedback & profiling, workshoping, wireframing and so on which is a whole different proposal.

What this is. Low hanging fruit, ie optimisations that could make this interface more intuitive, especially for people not familiar with mysql builder, or more used to Drupal Views syntax.

Proposals are grouped in four areas:

1. Language. For e.g. changing 'Where' to 'Filter', and 'Having' to 'Filter within Results', which would make clear both do similar things (filter), but how they are different.
2. Help tooltips. An (i) icon that can be clicked for a quick explanation of a term, plus a link to the docs where possible (ie 'WITH is a connection to another entity, like a MySQL JOIN or Views RELATIONSHIP. Learn more >>')
3. Pre-built Reports as Search Kit displays in the UI out-the-box. ie recreate some common CiviReports as SK displays that people can then tweak/clone/deconstruct, and in doing so learn a bit of the interface/structure. Inspired by the comment 'Tweaking is easier than creating'.
4. Reorder elements of the page to make the user journey more obvious. These should be doable either through CSS grid reordering, or minimal markup tweaks. E.g. (brainstormed ideas not proposals):
   • ensure all related blocks are within a parent visual container/border to keep them separate when queries get longer,
   • put some elements (ie group or query info) behind an 'advanced' expanding region,
   • move left column of searches and displays into top tabs to increase available page width,
   • rethink two columns in favour of list of blocks, similar to advanced search.

In addition @artfulrobot raised the issue of adding descriptive class names to regions to make it easier to target them.