Add disk usage sections to cli pages.
Revisions based on initial review.
add note for omero.jvmcfg.* setters about admin jvmcfg
Fix table alignment.
Merge pull request #992 from ximenesuk/disk-usage-plugin

Add disk usage sections to cli pages.
tweak jvmcfg text as suggested by @ximenesuk
Merge pull request #995 from mtbc/admin-jvmcfg-hint

add note for omero.jvmcfg.* setters about admin jvmcfg