readme: Replace resin with balena where appropriate
readme: Replace resin with balena where appropriate

To be more consistent in naming.

Change-type: patch
Signed-off-by: Roman Mazur <f5f3efb34fd910d428914ec0bcfa315dbb0117fd@gmail.com>

resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin