feat: add --no-delete option, resolves #224

[ramgp]

The user feedback is displayed in the header, I tried to make so that it disappears automatically after some time, but it seems to only update after some other action like moving in the list

Please let me know if this is good enough or if some other approach is preferred

Resolves #224.

[codecov]

Codecov Report

Attention: Patch coverage is 71.79487% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 89.96%. Comparing base (58ad4d3) to head (d7d5022).

Files	Patch %	Lines
cmd/gdu/app/app.go	0.00%	3 Missing and 1 partial ⚠️
tui/tui.go	75.00%	3 Missing and 1 partial ⚠️
tui/show.go	84.21%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #333      +/-   ##
==========================================
- Coverage   90.02%   89.96%   -0.07%     
==========================================
  Files          32       32              
  Lines        3469     3497      +28     
==========================================
+ Hits         3123     3146      +23     
- Misses        279      283       +4     
- Partials       67       68       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[dundee]

The ui code needs to be called inside ui.app.QueueUpdateDraw(func() { to handle concurrency properly. See https://github.com/rivo/tview/wiki/Concurrency#actions-in-goroutines for more details.

I will add few improvements/fixes to your PR.