Client:Add argument, change constants for sys-test
Client:Add argument, change constants for sys-test

For the systest to be able to use the client to test communication with a
caramel server an argument for the directory of the files used by the client
is added so that a system test can make use of a temporary directory. The
following constants has been changed:

CA_DIR : Temporary directory for files
CA_CERT, MY_CRT, MY_CSR, MY_KEY : change to support variable directory
CLIENTID : Now an UUID, the previous method for the MAC-addr is not universal
SUBJECT : Added more component to the subject to match what caramel_ca uses
POST_URL : Changed to use local IP instead of an arbitrary example address

ModioAB/caramel,ModioAB/caramel