OP-1296 only use GPS in filterchains when explicitly requested

disallow arming when GPS is needed for initialization until lock is acquired
Merge branch next into 'corvuscorax/OP-1296_barometer-initialization-fix'
OP-1296 - some explicit const declarations in stateestimation
Merge branch 'corvuscorax/OP-1296_barometer-initialization-fix_nextbased' into next