S3 bucket names are not validated against Amazon naming rules when adding a Data Connection

Description of problem:

A user can write anything in the name field for an S3 bucket when adding a new data connection, leading to anything relying on that DC to fail down the line because of the bucket name being wrong. 

Prerequisites (if any, like setup, operators/versions):

RHODS 1.21

Steps to Reproduce

1. Create DSG
2. Create Data Connection
3. Use an S3 bucket name that doesn't comply with https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucketnamingrules.html 

Actual results:

User can create a Data Connection with a bucket name that cannot exist

Expected results:

Input is validated against the naming rules in the S3 docs (https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucketnamingrules.html ) and user is not allowed to create such a data connection.

Ideally, the backend should also try accessing the bucket on the fly to confirm that it exists and that the given credentials are working.

Reproducibility (Always/Intermittent/Only Once):

Always

Build Details:

RHODS 1.21

Workaround:

Additional info: