Refactoring form controller logic to base class for reuse

[Benjin]

Moving some of the sharable logic for forms to a base class. Other form UIs (like container deployment) should be able to reuse the formAction reducer, validation, and error reporting now.

[github-actions]

PR Changes

Category	Main Branch	PR Branch	Difference
Code Coverage	50.66%	50.77%	$.11\mathrm{\%}$
VSIX Size	12982 KB	12983 KB	$1KB(0\mathrm{\%})$
Webview Bundle Size	3188 KB	3188 KB	$0KB(0\mathrm{\%})$