rfc: client certificates for servers using SMP protocol as clients (opertors' chat relays, notification servers, service bots) (#1534)

* rfc: client certificates for high volume clients (opertors' chat relays, notification servers, service bots)

* client certificates types (WIP)

* parameterize Transport

* protocol/schema/api changes

* agent API

* rename command

* agent subscriptions return local ClientServiceId to chat

* verify transmissions

* fix receiving client certificates, refactor

* ntf server: remove shared queue for all notification subscriptions (#1543)

* ntf server: remove shared queue for all notification subscriptions

* wait for subscriber with timeout

* safer

* refactor

* log

* remove unused

* WIP service subscriptions and associations, refactor

* process service subscriptions

* rename

* simplify switching subscriptions

* SMP service handshake with additional server handshake response

* notification delivery and STM persistence for services

* smp server: database storage, store log, fix encoding for STORE error, replace String with Text in locks and error

* stats

* more stats

* rename SMP commands

* service subscriptions in ntf server agent (tests fail)

* fix

* refactor

* exports

* subscribe ntf server as service for associated queues

* test ntf service connection, fix SOKS response, fix service associations not removed in STM storage

* INI option to support services

* ntf server: downgrade subscriptions when service is no longer supported, track counts of subscribed queues

* smp protocol: include service certificate fingerprint in the string signed over with entity key (TODO two tests fail)

* fix test

* ntf server prometheus stats, use Int64 in SOKS/ENDS responses (to avoid conversions), additional error status for ntf subscription

* update RFC

* refactor useServiceAuth to avoid ad hoc decisions about which commands use service signatures, and to prohibit service signatures on other commands

* remove duplicate service signature syntax check from checkCredentials, it is checked in verifyTransmission

* service errors, todos

* fix checkCredentials in ntf server, service errors

* refactor service auth

* refactor

* service agent: store returned queue count instead of expected

* refactor serverThread

* refactor serviceSig

* rename

* refactor, rename, test repeat NSUB service association

* respond with error to SUBS

* smp server: export/import service records between database and store log

* comment

* comments

* ghc 8.10.7

src/Simplex/FileTransfer/Client.hs

@@ -116,7 +116,7 @@ getXFTPClient transportSession@(_, srv, _) config@XFTPClientConfig {clientALPN,
   let HTTP2Client {sessionId, sessionALPN} = http2Client
       v = VersionXFTP 1
       thServerVRange = versionToRange v
-      thParams0 = THandleParams {sessionId, blockSize = xftpBlockSize, thVersion = v, thServerVRange, thAuth = Nothing, implySessId = False, encryptBlock = Nothing, batch = True}
+      thParams0 = THandleParams {sessionId, blockSize = xftpBlockSize, thVersion = v, thServerVRange, thAuth = Nothing, implySessId = False, encryptBlock = Nothing, batch = True, serviceAuth = False}
   logDebug $ "Client negotiated handshake protocol: " <> tshow sessionALPN
   thParams@THandleParams {thVersion} <- case sessionALPN of
     Just "xftp/1" -> xftpClientHandshakeV1 serverVRange keyHash http2Client thParams0
@@ -132,7 +132,8 @@ xftpClientHandshakeV1 serverVRange keyHash@(C.KeyHash kh) c@HTTP2Client {session
   (vr, sk) <- processServerHandshake shs
   let v = maxVersion vr
   sendClientHandshake XFTPClientHandshake {xftpVersion = v, keyHash}
-  pure thParams0 {thAuth = Just THAuthClient {serverPeerPubKey = sk, serverCertKey = ck, sessSecret = Nothing}, thVersion = v, thServerVRange = vr}
+  let thAuth = Just THAuthClient {peerServerPubKey = sk, peerServerCertKey = ck, clientService = Nothing, sessSecret = Nothing}
+  pure thParams0 {thAuth, thVersion = v, thServerVRange = vr}
   where
     getServerHandshake :: ExceptT XFTPClientError IO XFTPServerHandshake
     getServerHandshake = do