Display blueprint configuration's relationship to default configuration

[kpreid]

Is your feature request related to a problem? Please describe.
Rerun comes up with a default blueprint based on the logged data, then allows you to customize it. However, there is no indication that this customization has been done, and remembered for future sessions, which makes an important part of the Rerun workflow totally invisible.

Describe the solution you'd like
In the blueprint tree and settings sidebar, make some visual distinction between views and entities which have had their blueprint customized, and ones which have not. That is, display what pushing the ↺ "Re-populate Viewport" button would reset.

A further refinement might be to also distinguish new entities, which have not only not been customized, but also did not exist in previous recordings; this conveys “you might want to customize this” and also provides a possibly useful cue when doing development work on the data source/application.