Update key pair migration task to:

handle key pair name duplication, and add an attribute "new_name" to store the new key pair name in the destination cloud
Merge branch 'master' of https://github.com/Phoenix1708/OpenAcademy_OpenStack_Flyway
Update get_keypairs in web:

output all key pairs in the 'key_pairs' table in the source cloud, instead of only key pairs of 'admin'