add github files

[james-bruten-mo]

Update the lfric_core pr template, .gitignore and Readme files. Also add the check-cr-approved workflow to check that the assigned code reviewer has approved the PR.

Question for Steve and Andy is whether the original licence file should remain in place?

[stevemullerworth]

Question for Steve and Andy is whether the original licence file should remain in place?

I think it would be fine to remove the original licence as there is no difference between the two licences. We have two only because we didn't think enough about the separation between the licence and the copyright (there are two alternative copyright statements in lfric_core).

However, the references in the older files that contain the alternative "Queens Printer" copyright would need to change to point to LICENCE instead of LICENCE.original.

[james-bruten-mo]

Thanks Steve, I've done that. It's made this ticket quite a bit bigger, so if you'd prefer I revert that then no problem

[andrewcoughtrie]

Perhaps a little bit of comment to say that these will auto close the issue as not all of these examples will.

[andrewcoughtrie]

This all looks good to me now.