The main command for generating DKIM keys (`opendkim`) wasn't installed with just the `opendkim` package. Added a fix so it would be installed should it not be there the first time `apt` is ran.
default /etc/opendkim.conf has KeyTable appear in comment doco and example.
Shouldn't trigger the grep that checks whether this config has been applied.
Deleting all settings starting with o seems rather arbitrary, but I don't know the default configuration on Vultr, so could be warranted :) But I'll be bold and guess the `sed` command and the following lines are supposed to be related?