Add section about delete functions
Replace OMERO_HOME environment variable by OMERO_PREFIX
Replace OMERO_HOME by OMERO_SOURCE_PREFIX when pointing at source code
Unify users' naming, reformulate a confusing sentence
Add documentation fixes as per J-M's suggestion
Minor fixes and increasing consistency in sysadmin docs.
Delete outdated note, format lists according to guidelines
merge dev_4_4 -D org -I include -E exclude: PR 281 (Review Matlab documentation (see #10389))
merge dev_4_4 -D org -I include -E exclude: PR 291 (Add "Link" action to permissions table and to the Key 4)
merge dev_4_4 -D org -I include -E exclude: PR 296 (Putting OME-XML formats docs into ome-docs repo)
merge dev_4_4 -D org -I include -E exclude: PR 310 (Do not expose OMERO_HOME in the doc (see #10603))
merge dev_4_4 -D org -I include -E exclude: PR 311 (Minor fixes and increasing consistency in sysadmin docs.)