Convert images to webp

[AliJonMadaminov]

Flag images are in png format, their size can be significantly reduced by converting to webp.

[offvanHooijdonk]

Moreover, I can see them as SVG files in repo, but when I add the lib within Gradle - the resource that I get is PNG, not SVG, and I cannot use it in Icon, i should use Image function instead which is wired