Update integrations section in Platforms and Distributions

[hillaryfraley]

Description

• Change "Integrations" heading to to "Configuration Management Integrations" and add some explanation.
• Need better placement or phrasing for Grafana item, which does not fit neatly into this section.

Category

This is an issue with:

• [ ] errata (error in doc content)
• [ ] new doc (requires a completely new doc)
• [ ] update (add missing or refresh existing content)
• [x] improvement (improve docs content or format)

Affected pages

https://docs.sensu.io/sensu-go/latest/platforms/#integrations

[hillaryfraley]

@cwjohnston I'm wondering if we might want to either:

• Move this content into the Platforms and Distributions page: https://docs.sensu.io/sensu-go/latest/installation/configuration-management/
• Remove the Integrations section from Platforms and Distributions in favor of keeping https://docs.sensu.io/sensu-go/latest/installation/configuration-management/

Of course, this does not answer how we should handle the Grafana plugin. I'm wondering if that shouldn't be handled as part of the Integrations section we discussed (see https://github.com/sensu/sensu-docs/issues/2379#issuecomment-643462318 -- Grafana Data Source is one of the cards from the Training trello board)

What do you think?