34531: ui: implement logical plan design r=celiala a=celiala

This commit implements the designs as specified in
Zeplin design "Logical Plans - v1":
https://app.zeplin.io/project/5c40e9dab2616abf79e3eb99/screen/5c4b6f23143de2bfcb12ae4e

Note that remaining design items will be addressed in future commits (tracked in #34545).

![logical-plans](https://user-images.githubusercontent.com/3051672/52312291-11070d80-2978-11e9-8ecc-42ab4a859371.gif)

Release note: None

34592: opt: Fix panic in SQLSmith query r=andy-kimball a=andy-kimball

A SQLSmith query exposed a bug in the expression interner. This bug caused
the interner to consider empty literal arrays to be equal, even if their
static types are different. For example:

  ARRAY[]:::string[]
  ARRAY[]:::int[]

An empty string array should not be treated as the same as an empty int
array. The fix is to consult the static type of the array in addition to the
types of its elements (but only when there are zero elements or one of the
elements is null). In addition, I took the opportunity to make the existing
Tuple interner code faster, by only comparing static types when lables or
nulls are present.

Fixes #34439

Release note: None
Co-authored-by: Celia La <[email protected]>
Co-authored-by: Andrew Kimball <[email protected]>