Issue description

ch03 missing primary use cases and pro's/Con's for both RGW and MCG.

My suggestions for MCG primary use cases and pro's/con's

Primary use case:
1. Require objects to be placed in multiple S3 endpoints, that can't replicate directly
2. When advanced policies are required, for placement of objects, between various s3 providers.

Pro's
1. Provides a unified endpoint for storing S3 objects in various S3 storage providers, based on policies
2. Lower total resource footprint on the OCP cluster, because it can be installed without installing the ODF storage component (Ceph)

Con's
1. Much less performant than RGW
2. Current design (at least until and including 4.19) is inherently SPoF.
3. Scrambles object names, making it problematic to identify data if client connects directly to the S3 storage
4. Doesn't do notifications, according to next pages picture
5. NooBaa is not highly available, according to chapter 5.1 / 5.2
6. I was unable to find confirmed configration maximums on MCG
7. I was unable to find recent performance metrics for MCG, the one I found is somewhat old and RGW is about an order of magnitude faster.