Remove "ced" dependency

[FlyingDR]

ced usage was removed by https://github.com/Helpmonks/haraka-plugin-mongodb/commit/d3a8b4697bdcf434c56ec8424f003691dba19d41, but it is still listed as a package dependency: https://github.com/Helpmonks/haraka-plugin-mongodb/blob/b2b8668576548d42a0decaca9b7304bf3e2b8b1f/package.json#L34 it would be good to remove it because it have own binary dependency which may require native binary build process during npm install without any practical purpose.