Allowing a user to change screencast mode overlay position and height/width from settings.

[matt-april]

• Added a new category to the workbench settings, Screencast Mode underneath Zen Mode. This gives us a place to put future screencast mode settings as more are requested.

• Added 4 new settings to the Screencast Mode category, Vertical Position, Horizontal Position, Height, and Width, with default values that match the current hard coded values.

• Updated developerActions.ts to pull the styles used for this overlay from the settings.

This fixes issue #66676.

[matt-april]

@joaomoreno Any chance I could get a reviewer on this PR? Wanted to make sure this PR doesn't slip through the cracks!

[joaomoreno]

@mattkwiecien Large backlog: https://github.com/Microsoft/vscode/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc+assignee%3Ajoaomoreno

[matt-april]

@mattkwiecien Large backlog: https://github.com/Microsoft/vscode/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc+assignee%3Ajoaomoreno

oh my... haha, no worries just wanted to make sure this didn't split through the crack!

god speed.

[joaomoreno]

I've just kept the vertical offset setting, I don't think we really need the other ones. Thanks! 🍻