Added support for logging in with Stellar

* Added PAMSG_STELLAR_LOGIN / PAMSG_STELLAR_LOGIN_RESPONSE, which is
  used by the client to request a login token that can be signed using a
  Stellar wallet.

* Added uWebSockets dependency, used to listen for a separate server
  that verifies signed tokens (the Stellar Bridge). When a token is
  verified, it is sent to manaserv-account, which then sends a
  APMSG_LOGIN_RESPONSE to the client matching the token.

* Added RapidJSON dependency to parse the JSON WebSocket messages.

* To keep everything in a single thread, uWebSockets is now driving the
  event loop. Processing of ENet hosts, writing stats and expired bans
  have been moved to uSocket timers.

* C++ standard updated to C++17, as required by uWebSockets.

When Stellar is used to login, the public key is used as the username.
It might be better to introduce an explicit field for this, especially
when we want to enable an account to feature both Stellar login as well
as login with username / password.

1 files changed, 0 insertions, 0 deletions

diff --git a/libs/uWebSockets b/libs/uWebSockets
new file mode 160000
+Subproject 67ed81b9f43832acab5d7f75a8cc38cdfd25c03