IC:2021-04-27, Add cfe changes, part 1

nasa/cFE#1379, memory pool pointer type
nasa/cFE#1289, ES child task functional test
nasa/cFE#1289, typo in macro name
nasa/cFE#1286, Remove broken BUILDDIR reference
nasa/cFE#1305, remove option for "osal_compatible"
nasa/cFE#1374, CFE_SUCCESS constant type
nasa/cFE#1316, Remove Unused Error Codes
nasa/cFE#1370, better warning about malformed startup line
nasa/cFE#1373, check status of call to `CFE_ES_CDS_CachePreload`
nasa/cFE#1384, update documentation for `CFE_ES_DeleteCDS`