S3C-380: Get security token
S3C-380: Get security token

Send security token to vault

See https://scality.atlassian.net/browse/S3C-380

scality/S3,scality/S3,scality/S3,scality/S3,tomateos/S3,tomateos/S3,scality/S3,scality/S3,tomateos/S3,scality/S3,tomateos/S3,scality/S3,tomateos/S3,tomateos/S3,tomateos/S3,tomateos/S3