add advanced settings to spark UI

[scottdraves]

to set all of these https://spark.apache.org/docs/latest/configuration.html

add a fold-out to the bottom of the Spark UI that exposes a UI for the advanced settings.
This could be as simple as a single multiline text box where user enters properties and values one per line.

but ideally editor like the one we have for JVM properties where you can add/remove lines,
each line has a name and a value in separate boxes. should this component be shared?

it would be GREAT if we could introspect and get some kind of autocomplete and validation and doc for all the properties :)