Output config: Automatically set the maximum spinbox values for output PWM pusle width.
BoardManager: Add virtual keyword to getChannelBanks()
OutputChannelForm: Change to qint32.
Output config: Resolved race condition

Previously, a race condition would occur when the ActuatorSettings UAVO
was updated before the board was recognized. This led to the spinbox
settings not being updated correctly.
Changes requested in review.
Merge pull request #980 from kubark42/output-pwm-maximum-as-function-of-channel-frequency

Output pwm maximum as function of channel frequency