- Only create the default repository if no repositories are
configured.
- Don't open repository window at startup if repositories are
configured.
This introduces an additional env variable `KOPIA_CUSTOM_APPDATA`
which is used in the tests but could be used in other scenarios as
well.
* test(ui): added minimal automated KopiaUI test
```
$ make kopia-ui-test
```
This currently executes super minimal E2E test on pre-built KopiaUI
using Playwright https://playwright.dev
* better os/arch detection
* remove unwanted log
* fixed executable path on linux
* fix for linux, misc
