Fix #124 (dirty hack):

This commit is a dirty hack to fix issue with ARM64 Prosody AppImage.
The fixed appimagebuild tool is not released by the dev team.
So i patch it in my build script. This is not a good solution, but it
works, and let me go forward.

server/lib/diagnostic/prosody.ts

@@ -40,7 +40,7 @@ export async function diagProsody (test: string, options: RegisterServerOptions)
         level: 'error',
         message: 'Error: no Prosody server.'
       })
-      if (process.arch !== 'x64' && process.arch !== 'x86_64') {
+      if (process.arch !== 'x64' && process.arch !== 'x86_64' && process.arch !== 'arm64') {
         result.messages.push({
           level: 'error',
           message: 'Error: your CPU is a ' +