chore: migrate Button to @revoltchat/ui (#617)

* chore: start moving Button over

* fix: convert ServerIdentityModal

* fix: modal button styling

* fix: popover styles

* fix: clean up references to ui/*.*

* fix: button sizing

Co-authored-by: Ed L <beartechtalks@gmail.com>

.prettierrc.js

@@ -4,6 +4,7 @@ module.exports = {
     jsxBracketSameLine: true,
     importOrder: [
         "preact|classnames|.scss$",
+        "^@revoltchat",
         "/(lib)",
         "/(redux|mobx)",
         "/(context)",