Refactored BACnetShedLevel encoding, decoding, and printing into separate file. Added unit testing. (#1187)

* Refactored BACnetShedLevel encoding, decoding, and printing into separate file.  Added unit testing.

* Added API to load control object for shed-level, start-time, duty-window, full-duty-baseline, and enable.

* Fixed bacapp sprintf for shed level and host-n-port found in scan build.

test/bacnet/basic/object/iv/CMakeLists.txt

@@ -53,6 +53,7 @@ add_executable(${PROJECT_NAME}
     ${SRC_DIR}/bacnet/hostnport.c
     ${SRC_DIR}/bacnet/lighting.c
     ${SRC_DIR}/bacnet/proplist.c
+    ${SRC_DIR}/bacnet/shed_level.c
     ${SRC_DIR}/bacnet/timer_value.c
     ${SRC_DIR}/bacnet/timestamp.c
     ${SRC_DIR}/bacnet/wp.c