proof of concept for quick filter of dialog list

[benbrown]

Description

• flatten dialog nav
• add quick filter at top that instantly filters list to include only matching dialog names

Task Item

Please include the link to the related work item, like fix Something is not working

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have functionally tested my change

Screenshots