Changes

[534578] Build MAT 1.8 against Photon
- set the default target to mat-photon
- update minimum required Java version to 1.8
- restrict the list of supported platforms (target configuration) to the 
ones supported by the Photon
- update the pre-filled update side in the product to photon
Change-Id: I3924862f11d143f03d198a5e2f001cc56346bc96 Signed-off-by: Krum
Tsvetkov <krum.tsvetkov@sap.com>