scripts: Add copyright statements to files without one
Where there isn't a copyright statement, add one to make it explicit.
Also drop editor config lines where they were present and add license
identifiers as MIT if there isn't one.
(From OE-Core rev: deb3ccec53e0bd63bc4235cf2b0d3fc781687361)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>