Give cloud provider storage blocks consistent names

[billpalombi]

Prefect Version

2.x

Describe the proposed behavior

Block schema names are consistent with each other:

• The "Azure" block schema is named "Azure Bucket"
• The "GCS" block schema is named "GCS Bucket"
• The "S3" block schema is named "S3 Bucket"

Describe the current behavior

Cloud provider storage blocks have inconsistent names

Example Use

No response

Additional context

No response