Integrate meta-seconorth-distro/refactor_DISTRO_FEATURES_removal

Commit: seco-ne/yocto/layers/meta-seconorth-distro@c738078b

seconorth-wayland: Refactor DISTRO_FEATURES:remove

The Yocto system for appending and removing items form lists executes the removal as a last step. After a removal an item cannot be appended.

For the DISTRO_FEATURES this means that the once removed "x11" item cannot be appended in later steps or dependent layers.

This can be circumvented by the introduction of intermediate variables or by using such variables.

For example poky defines DISTRO_FEATURES as follows

DISTRO_FEATURES ?= "${DISTRO_FEATURES_DEFAULT} ${POKY_DEFAULT_DISTRO_FEATURES}"

To remove an item from the DISTRO_FEATURES you can instead remove it form one of the variables i.e. the DISTRO_FEATURES_DEFAULT variable.

Thus remove the bluetooth and x11 items from the DISTRO_FEATURES_DEFAULT to be able to re-add them to DISTRO_FEATURES later.