Initial ProgressView implementation

[jvalkeal]

Component to show progress info. Some influence i.e. from https://rich.readthedocs.io/en/stable/progress.html and https://github.com/npkgz/cli-progress.

• [x] Basic items, text/spinner/percent
• [x] Events for start/stop/change
• [x] Styling - needs new settings class in theme system
• [x] Scenario sample
• [x] Initial Docs

[jvalkeal]

Initial work done, further development in a separate issues.