Add icon for expandable code editor and explore what Monaco allows for with scrolling

[rebeccaalpert]

RHDH PM requested an expandable code editor - could use custom actions and change the height. May want to explore what Monaco allows for here before opening a design issue. Design is willing to supply an icon.

Editing because I realized that we discussed the code editor - this is actually the code block. We can probably get by with the expandable example and recolor it: https://www.patternfly.org/components/code-block/.