Brand the webmail INBUXA: name, mark and wordmark

INBUXA is a product suite and ihasmail an independent product, so INBUXA's
webmail says INBUXA: the sign-in page, header, page title, installed-app name
and About page. The wordmark is drawn in the current text color. ihasmail's
version and AGPL source line stay as its credit. Two new strings, in all nine
catalogues; three Stalwart-only ones are no longer used.

server/src/config.ts

@@ -278,7 +278,7 @@ if (oauthClientSecret && !publicUrl) {
 
 export const config = {
   isProd,
-  appName: env("APP_NAME", "ihasmail"),
+  appName: env("APP_NAME", "INBUXA"),
   settingsPolicy: readSettingsPolicy(),
   /**
    * What this build calls itself: `2.16.57`. Set by the image build from