Add examples to salt-run proposal.help

[Martin-Weiss]

Description of Issue/Question

When ever we create new storage profiles we need to assemble the command line for these based on the parameters we can find in "salt-run proposal.help".

It would be great if we could have some examples for typical setups as part of that help text.

Could we add some like this with some description?

salt-run proposal.populate target='ses-osd-0*' name=dd ratio=4 db-size=50G wal-size=2G nvme-spinner=true

This creates a proposal with the name "profile-dd" for all servers starting with ses-osd-0 where the wal and rocksdb are stored on the same NVMe with a rocksdb size of 50GB and a WAL size of 2 GB.