feat(flysky): Flysky Gimbal 2.0 Sync Sampling Support

[richardclli]

Flysky works out a new version of firmware that can support sync sampling:

1. Upon init the gimbal will operate in backward compatible mode (i.e. old EdgeTX will works after the gimbal firmware is upgraded)
2. New firmware will check the version of the firmware to see if sync mode is supported
3. New driver will send command to the gimbal for sync sampling

The gimbal driver changes:

1. It will automatic obtain the version of the gimbal to check if sync sampling is available
2. The default operation mode is backward compatible mode, will switch to sync modes only when new version of gimbal firmware is detected
3. Based on sampling frequency, the driver will automatically switch to sync sampling mode (<= 400Hz - switching threshold) or sync resampling mode (> 400Hz)

Testing:

1. Not breaking the operation of existing old gimbals including the gimbal of GX12
2. Flysky firmware seems to have some problems now, trying to verifying with them.

[raphaelcoeffic]

I haven't checked the protocol itself, only the sync trigger / wait for now.

[pfeerick]

As the exact implementation for this is WiP, I'm going to kick this over to v2.11.1

[richardclli]

@raphaelcoeffic Need your review and comment on this:

1. The gimbal need to config the mode of operation whenever the tx sampling rate changes, currently the gimbal driver times the trigger call from the mixer and select the mode of operation. Not sure if there are more direct approach e.g. direct read the sampling freq used in the mixer. But not sure how to implement this.
2. Currently, the gimbal sampling will be triggered after the ADC finished. It will be best to run in parallel with ADC, but I tried this and ADC will have strange behavior. The readings will just jumps without touching the hardware controls.

[richardclli]

Flysky just send me a new gimbal firmware that fixes their bugs, no need any changes on this PR.