Tidy EdgeDBConnection class. (#89)

- Add `TLSServerName` and support for it in the clients
- Ensure consistent ordering and naming of properties and backing fields.
- Fix parsing of TLS security mode
- Remove some checks in property setters, they will be re-added later.

src/EdgeDB.Net.Driver/Clients/EdgeDBBinaryClient.cs

@@ -57,7 +57,7 @@ public EdgeDBBinaryClient(
         Connection = connection;
         ServerKey = new byte[32];
         MessageTimeout = TimeSpan.FromMilliseconds(clientConfig.MessageTimeout);
-        ConnectionTimeout = TimeSpan.FromMilliseconds(connection.Timeout);
+        ConnectionTimeout = TimeSpan.FromMilliseconds(connection.WaitUntilAvailable);
         _stateDescriptorId = CodecBuilder.InvalidCodec;
         ClientConfig = clientConfig;
         _semaphore = new SemaphoreSlim(1, 1);

src/EdgeDB.Net.Driver/Clients/EdgeDBTcpClient.cs

@@ -97,7 +97,7 @@ or SocketError.HostNotFound
         {
             AllowRenegotiation = true,
             ApplicationProtocols = new List<SslApplicationProtocol> {new("edgedb-binary")},
-            TargetHost = Connection.Hostname,
+            TargetHost = Connection.TLSServerName ?? Connection.Hostname,
             EnabledSslProtocols = SslProtocols.None,
             CertificateRevocationCheckMode = X509RevocationMode.NoCheck
         };

src/EdgeDB.Net.Driver/EdgeDBClient.cs

@@ -343,9 +343,9 @@ internal async Task<BaseEdgeDBClient> GetOrCreateClientAsync(CancellationToken t
                 {
                     token.ThrowIfCancellationRequested();
                     return _availableClients.TryPop(out result);
-                }, (int)_connection.Timeout)
+                }, (int)_connection.WaitUntilAvailable)
                     ? result!
-                    : throw new TimeoutException($"Couldn't find a client after {_connection.Timeout}ms");
+                    : throw new TimeoutException($"Couldn't find a client after {_connection.WaitUntilAvailable}ms");
 
                 client.AcceptHolder(await _poolHolder.GetPoolHandleAsync(token).ConfigureAwait(false));
                 return client.WithSession(_session);