libcolord: Ensure the parsed EDID strings are valid UTF-8
libcolord: Check that both the metadata key and value are valid UTF-8
libcolord: Add a trivial check to ensure the EDID checksum is non-NULL

I don't think this can happen in reality.
libcolord: Check that the ICC vendor and model strings are valid UTF-8
libcolord: Do not write an invalid dict or mluc data when the resaving a profile
libcolord: Ensure the version is set when using cd_icc_create_from_edid()

Although this looks trivial as just the version isn't set, it's actually an
important bug as if we write the file we write a v2 file as the version < 4.0.