server: Add channel handling for location channel ([MS-RDPEL])

With the location channel, an RDP server can redirect the location of
the user from the client side to the server side.
The PDUs are almost the same as in the documentation, except for the
encoded types, these ones are here already parsed.
Optional values are accessed via pointers. If the pointer of a value is
NULL, then that value was not supplied by the client side.

channels/location/CMakeLists.txt

@@ -0,0 +1,22 @@
+# FreeRDP: A Remote Desktop Protocol Implementation
+# FreeRDP cmake build script
+#
+# Copyright 2023 Pascal Nowack <Pascal.Nowack@gmx.de>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+define_channel("location")
+
+if(WITH_SERVER_CHANNELS)
+	add_channel_server(${MODULE_PREFIX} ${CHANNEL_NAME})
+endif()