Flyingf3 shields also fixes #546

Created a shields UAVO object under Hw settings.
This is used to init the ADC pins.

The recent ADC merge broke CC this branch also fixes it and fixes some bugs on the F3 ADC.
Even if it is working and tested there is still something fishy, I had to reduce the ADC clock rate or the board would hang (slow LED, CPU error and non working PFD). Reverting to 556ef7d758ab52acd8a76129084aabafe52c26fc for example fixes those problems but I don't see anything ADC related which could cause that.
Right now with the reduced ADC clock I still have a yellow CPU on the flyingF3 but that only happens with the shield set as "RCFlyer" which enables the ADC so I'm opening this PR so we can have next working again.

Fixes #329