MTV-1433 Rearranging prerequisites in the MTV user guide

[RichardHoch]

MTV 2.8

Partially resolves https://issues.redhat.com/browse/MTV-1433 by grouping prerequisites by vendor (VMware, RHV, etc.) where possible.

Previews:

• https://file.corp.redhat.com/rhoch/prereqs_by_provider/html-single/#prerequisites_mtv [Introduction and compatibility requirements]
• https://file.corp.redhat.com/rhoch/prereqs_by_provider/html-single/#vmware-prerequisites_vmware [VMware prerequisites]
• https://file.corp.redhat.com/rhoch/prereqs_by_provider/html-single/#rhv-prerequisites_rhv [RHV prerequisites]
• https://file.corp.redhat.com/rhoch/prereqs_by_provider/html-single/#openstack-prerequisites_ostack [OpenStack prerequisites]
• https://file.corp.redhat.com/rhoch/prereqs_by_provider/html-single/#ova-prerequisites_ova [OVA prerequisites]
• https://file.corp.redhat.com/rhoch/prereqs_by_provider/html-single/#openshift_virtualization_prerequisites [CNV prerequisites]

Note -- Some port information is missing. This is indicated by "TBD".

[RichardHoch]

@nunzy1 I made many of the changes you suggested and did a little other rewriting. Please review this PR again. Thanks.

[RichardHoch]

@mnecas @fabiand Please review this PR. It is the 4th and final PR (hopefully) in the "restructure the user guide" epic.

[fabiand]

A few things to change.

[fabiand]

If we know for sure that it fails, then we should reword to

Hibernation must be disabled because {project-first} does not support migrating hibernated VMs.

[RichardHoch]

@mnecas Do we know for sure migration fails for hibernated VMs? If I remember correctly, it might fail, it might not, so we phrased it as "strongly recommended to disable", but please keep me honest. @fabiand

[RichardHoch]

@fabiand @mnecas Please note that information about ports is still missing: https://issues.redhat.com/browse/MTV-1714