feat(block storage): create guide about choosing classes

[OvhValentin]

What type of Pull Request is this?

• New guide(s)
• Index categories update

Description

Refer to SK-2471

Mandatory information

The translations in this Pull Request have been done using:

• [ ] OVHcloud integrated translation LLM
• [ ] Systran
• [ ] Other tool (specify which tool was used)
• [ ] This Pull Request didn't require any translation.

• This Pull Request can be merged as soon as possible.

• This Pull Request content should be replicated for the US OVHcloud documentation : YES/NO

[OvhValentin]

not ready

[Y0Coss]

@OvhValentin , please edit the index file and indicate which translation tool was used.

[benchbzh]

Thank you for your contribution @OvhValentin!