Registartion templates updated


**Functionalities implemented:**

1) Registration templates updated
 
   - For time being wherever possible, implemented {% trans %} template-tag and for remaining ones implemented {% blocktrans %} template-tag
   
   - Files modified:
   
     1) templates/registration/password_reset_complete.html
     2) templates/registration/password_reset_email.html
     3) templates/registration/password_reset_email_subject.txt