Enable permessage-deflate for chat connections

Switches the tungstenite dependency from stock v0.27 to our fork. Enables the 
"deflate" feature of the same, and adds a remote config flag to enable 
negotiating permessage-deflate support when establishing a chat connection.

LibSignalClient.podspec

@@ -15,6 +15,7 @@ Pod::Spec.new do |s|
 
   s.swift_version    = '5'
   s.platform         = :ios, '15.0'
+  s.libraries        = ['z']
 
   s.source_files = ['swift/Sources/**/*.swift', 'swift/Sources/**/*.m']
   s.preserve_paths = [