samples: Bluetooth: df: Remove dep on CTLR Kconf in sample sources

Direction finding samples had dependency on KConfig option defined
in Controller. That caused a problem for split builds where
an application and host are not part of the same binary as
controller. The code dependend on the Kconfig option
was always disabled.

To fix that issue new Kconfig options were introduced to
Host. The dependency is removed. Unwanted features may stil be
disabled and samples binaier will be smaller.

The commit aligns all direction finding samples code.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>