brcm2708: update image names and manifest aliases for new libplatforminfo

targets/brcm2708-bcm2708

 include 'brcm2708.inc'
 
-device('raspberry-pi', 'rpi', {
+device('raspberrypi-model-b', 'rpi', {
 	manifest_aliases = {
+		'raspberrypi-model-b-plus',
+		'raspberrypi-model-b-rev2',
+
+		-- from Gluon 2019.1 and older
 		'raspberry-pi-model-b-rev-2',
 		'raspberry-pi-model-b-plus-rev-1.2',
 	},

targets/brcm2708-bcm2709

 include 'brcm2708.inc'
 
-device('raspberry-pi-2', 'rpi-2', {
+device('raspberrypi-2-model-b', 'rpi-2', {
 	manifest_aliases = {
+		-- from Gluon 2019.1 and older
 		'raspberry-pi-2-model-b-rev-1.1',
 	},
 })

targets/brcm2708-bcm2710

 include 'brcm2708.inc'
 
-device('raspberry-pi-3', 'rpi-3', {
+device('raspberrypi-3-model-b', 'rpi-3', {
 	manifest_aliases = {
+		'raspberrypi-3-model-b-plus',
+
+		-- from Gluon 2019.1 and older
 		'raspberry-pi-3-model-b-rev-1.2',
 	},
 })