admin-info: Include delete markers count

[krisis]

Description

Add total number of delete markers to the usage summary section of admin-info output.

Motivation and Context

To allow users to track unusual application behavior like creating excessive delete markers, usually since the application is not bucket versioning aware.

How to test this PR?

mc admin info ALIAS

Sample output

mc admin info play
●  play.min.io
   Uptime: 5 hours
   Version: 2023-07-19T05:25:12Z
   Network: 1/1 OK
   Drives: 4/4 OK
   Pool: 1

Pools:
   1st, Erasure sets: 1, Drives per erasure set: 4

11 GiB Used, 428 Buckets, 38,035 Objects, 54,636 Versions, 26,363 Delete Markers
4 drives online, 0 drives offline

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here

[harshavardhana]

How about we reformat it like this

mc admin info play
●  play.min.io
   Uptime: 5 hours
   Version: 2023-07-19T05:25:12Z
   Network: 1/1 OK
   Drives: 4/4 OK
   Pool: 1

Pools:
   1st, Erasure sets: 1, Drives per erasure set: 4

Used   |  Buckets  |  Objects | Versions | Delete Markers |
11 GiB |  428      |  38,035  | 54,636   | 26,363         |

4 drives online, 0 drives offline

[vadmeste]

LGTM