boards/samd21-based: Model features in Kconfig

[jia200x]

Contribution description

This PR models the features for samd21 based boards and adds them to the Kconfig_features test whitelist.

Testing procedure

It should be enough to check that the Kconfig_features test works for all these boards (this means the list of provided features is equivalent):

BOARD=arduino-mkr1000 make && \
BOARD=arduino-mkrfox1200 make && \
BOARD=arduino-mkrwan1300 make && \
BOARD=arduino-mkrzero make && \
BOARD=arduino-zero make && \
BOARD=feather-m0 make && \
BOARD=hamilton make && \
BOARD=samd21-xpro make && \
BOARD=samr21-xpro make && \
BOARD=sensebox_samd21 make && \
BOARD=serpente make && \
BOARD=sodaq-autonomo make && \
BOARD=sodaq-explorer make && \
BOARD=sodaq-one make && \
BOARD=sodaq-sara-aff &&\
echo "OK"

Issues/PRs references

Depends on #13404
#14148

[leandrolanzieri]

This needs rebasing

[leandrolanzieri]

This needs rebasing and adapting to the new classification

[leandrolanzieri]

@jia200x ping!

[leandrolanzieri]

@jia200x will not be having time so he said it's ok to take over. I rebased and applied some fixes.

@fjmolinas maybe you can take a look?

[aabadie]

Looks good, just one minor nit. Please rebase!

[leandrolanzieri]

Rebased once more :)

[aabadie]

Rebased once more :)

Same here, I was also on it :)

[aabadie]

All good, ACK!