Companion trainer modes OFF and Master-Multi available for all radios

[elecpower]

Fixes #1796

Summary of changes:

• update trainer modes list item availability
• standardise trainer mode Off to OFF

[TheIsotopes]

@pfeerick Can not find commit 82c6181 in 2.7 Branch the over two commits from this PR are merged?!

EDIT: Ah now I see this PR here hasn't been merged into 2.7 branch yet. sry ;-)

[pfeerick]

I was trying Fork for the cherry-picking for the first time, and ended up merging the commits separately rather than the squash merge... so it is in 2.7 ;)

0305ac7
6a22b0a

[TheIsotopes]

@pfeerick pls, as you can see the commit 82c6181 with german translation fix was not landing in 2.7 branch.

edgetx/radio/src/translations/de.h.txt

Lines 326 to 336 in f4c0928

	#define LEN_VTRAINERMODES "\022"
	#define TR_VTRAINER_MASTER_OFF "OFF\0 "
	#define TR_VTRAINER_MASTER_JACK "Lehrer/Buchse\0 "
	#define TR_VTRAINER_SLAVE_JACK "Schüler/Buchse\0 "
	#define TR_VTRAINER_MASTER_SBUS_MODULE "Lehrer/SBUS Modul\0"
	#define TR_VTRAINER_MASTER_CPPM_MODULE "Lehrer/CPPM Modul\0"
	#define TR_VTRAINER_MASTER_BATTERY "Lehrer/Serial\0 "
	#define TR_VTRAINER_BLUETOOTH TR("Master/BT\0 ""Slave/BT\0 ", "Master/Bluetooth\0 ""Slave/Bluetooth\0 ")
	#define TR_VTRAINER_MULTI "Master/Multi"

[pfeerick]

Dammit... no, that commit isn't... I'll add it now so it goes into what is likely to be 2.7.0 baring a reason for a RC3...