Root password reset command (rebased onto develop)



This is the same as gh-794 but rebased onto develop.

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The `bin/omero` command for generating the password reset sql was missing. I've added it back and also updated the output to match the current output when setting the password to `ome`. However, this is different to the `openssl` commands in the previous paragraph, presumably because we're now salting passwords by default. I'm don't know how to fix that.