Converted CLI:sccp message device to CLI/AMI:SCCPMessageDevice. Added comments to explain how to use CLI_AMI_ENTRY macro's

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4782 43c1dc8c-776e-4df2-8ef1-6e829299be21
Converted CLI:sccp system message to CLI/AMI:SCCPSystemMessage.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4783 43c1dc8c-776e-4df2-8ef1-6e829299be21
Converted CLI:sccp dnd device to CLI/AMI:SCCPDndDevice.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4784 43c1dc8c-776e-4df2-8ef1-6e829299be21