[OE-core] meta-oe and oe-core mirror repos going away at the end of June

[Philip Balister]

For several "years", we have maintained two copies of the
openembedded-core and meta-openembedded repositories on github. At OEDAM
we decided it is time to go ahead and remove the repos with the old
names oe-core and meta-oe to lower the confusion level about what is in
these repos.

Please update build scripts and git config files with the current names,
openemebdded-core and meta-openembedded.

Thanks,

Philip