doc/cephadm: small improvements to services/index.rst

doc/cephadm: small improvements to services/index.rst

Remove "*" around CLI command placeholders that was rendered in literal strings.
Leave only the usual "<placeholder>" string.

Use the standard style section title preceding newlines.
Use double backticks consistently for literal strings.
Rewrap only excessively long lines only in certain places to avoid excessive diff.
Use confval role instead of literal inline for config keys in text.
Improve markup.

Fix word capitalization and minor changes to words.
Use Monitor, Manager, etc. instead of MON, MGR, etc.
Reword to "a command of the following form" where suitable.
Remove repetition in admonition about daemon status refresh.

Delete spaces at end of lines. Add full stops or colons.

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