[RFE] Gather sosreports with must-gather

1. Proposed title of this feature request

[RFE] Gather sosreports with must-gather

2. What is the nature and description of the request?

Currently, users must gather sosreports for each of their nodes individually. The process is a bit cumbersome as users have to use ssh or `oc debug node/...` followed by chroot and toolbox to generate a sosreport. They must then copy the sosreport out, manually and upload it to a customer case.

By adding this functionality to a collection script, we can make life easier for our customers and users.

The script would not be run by default, instead, admins would have to call it manually, the same as gather_core_dumps

3. Why does the customer need this? (List the business requirements here)

We ask the customer regularly to gather large sets of sosreports and they find the current steps too tedious. Having the must-gather image optionally gather sosreports would simplify necessary steps for our customer.

4. List any affected packages or components.
must-gather / https://github.com/openshift/must-gather