Dopr attachments_email_templates join table

[#51985479]

Mdm::Attachment and Mdm::EmailTemplate no longer exist, so no need for a
join table between them.
Drop attachments table

[#51985479]

Drops attachments table that is no longer needed because
Mdm::Attachments no longer exists.
Drop email_addresses

[#51985479]

The email_addresses table was used by the old-style campaign model
Mdm::EmailAddress, which is no longer defined, so the table can be
removed.
Drop email_templates

[#51985479]
Drop web_templates

[#51985479]
Drop campaigns

[#51985479]
Bump version number.

[#51985479]

Increment PATCH number since tables should have been deleted when models
were removed (and MINOR was incremented), so it's only a bug fix to remove the tables.
Merge pull request #31 from rapid7/bug/obsolete-campaign-tables

Drop obsolete campaign tables
Enforce 3.x Rails for now
More specificity for Rails
fix nexpose console validation

requiring ip address negates
hostname usage
fix migration issues

bad migration issues with pro, fixed up
Merge in latest master to resolve conflicts.