(core) Adding colors to toast notification

Summary:
Styling toast notification. Adding colors and icons.
In Grist, changed the default style for errors (will be shown in red), and a style for
Linked copied to clipboard (will be shown in Green).
All other colors are not used currently, left for another diff.

Test Plan: manual

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D3053

app/client/models/AppModel.ts

@@ -139,7 +139,7 @@ export class TopAppModelImpl extends Disposable implements TopAppModel {
         }
         if (org.billingAccount && org.billingAccount.product &&
             org.billingAccount.product.name === 'suspended') {
-          this.notifier.createUserError(
+          this.notifier.createUserMessage(
             'This team site is suspended. Documents can be read, but not modified.',
             {actions: ['renew', 'personal']}
           );