doc/install: Small improvements in manual-freebsd-deployment.rst

doc/install: Small improvements in manual-freebsd-deployment.rst

Update text and commands for the cluster vanity name deprecation:
- Explain that vanity names are deprecated (taken from ceph-conf.rst).
- Remove cluster name parameters from commands.
- Change cluster name variable in commands to simply "ceph".

Linkify some terms in the introduction text.

Use double backticks for data like paths, files consistently.

Don't capitalize in the middle of a sentence.
Don't capitalize "daemons".
Capitalize "MDS", the concept, consistently.

Missing space in "disk format", "disk layout", "discussion list".
Fix typoed "comingling", "resolved".
Fix copypasta zpool command that is supposed to add cache and not log.

Try to improve grammar and add missing full stops.
Use admonitions for note paragraphs.

Remove trailing '/' from directory path to be consistent with other
paths.

Fix missing empty line causing RST syntax rendered verbatim and with
wrong formatting.

Replace all tabs with four spaces.
Wrap very long text line.

Don't render colon in "Some text.:" preceding preformatted blocks.

Try to fix a preformatted table with columns all over the place.
Checked how it should look on Quincy but the output is different.

Promptify CLI commands but don't touch the long list of installation
commands. They might need reviewing anyways.

Signed-off-by: Ville Ojamo <14869000+bluikko@users.noreply.github.com>