Add proper support for LDAP

Previously, we implemented LDAP auth mechanism in core tarantool. This MR aims to add support for LDAP to picodata connect and a few other api methods, namely pico.create_user & pico.change_password. It also fixes a few bugs discovered in the progress.

Related: picodata/tarantool!82.

src/connect.lua

 local console = require("console")
+local uri = ...
+
 local TIMEOUT_INFINITY = 100 * 365 * 86400
-local arg = ...
+local opts = {}
+opts.timeout = TIMEOUT_INFINITY
 
 console.on_start(function(self)
     local status, reason
-    status, reason = pcall(
-        console.connect,
-        arg,
-        {connect_timeout = TIMEOUT_INFINITY}
-    )
+    status, reason = pcall(console.connect, uri, opts)
     if not status then
-        self:print(reason)
-        os.exit(0)
+        -- `type(reason) == cdata`, so we have to convert it
+        self:print(tostring(reason))
+        os.exit(1)
     end
-end)
-
-console.on_client_disconnect(function(_)
-    os.exit(0)
+    -- We should only set this after we try to connect, because
+    -- `console.connect` will call this before throwing eval errors
+    console.on_client_disconnect(function(_)
+        os.exit(0)
+    end)
 end)
 
 return console.start()