This commit introduces a concept of mesh-local IPv6 addresses. Such
addresses should only be used for mesh-local communication, therefore
should not be used to communicate with different subnets (i. e.
destinations outside the mesh).
As `addr_type` field already holds different kind of information
(whether address was created automatically/manually) it was not used in
this case.
Instead a mesh_local flag was added, so that we do not lose information
on how address was created. Address with such flag set will only be
selected as a source address automatically if the destination address
is within the same subnet it belongs to.
Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
83b8abaf8a