documentation

Pull request #1502: feature/ZBXNEXT-5120-7.0-D. Extended support of macro functions.

Merge in WEB/documentation from feature/ZBXNEXT-5120-7.0-D to release/7.0

* commit '94bbb045be5c498592ed8c199d13a43ae928932a':
  [ZBXNEXT-5120] Updated table formatting
  [ZBXNEXT-5120] Added note & link to macro functions in relavant pages
  [ZBXNEXT-5120] fmttime() function 'time_shift' parameter is optional
  [ZBXNEXT-5120] Restructured information on macro function support
  [ZBXNEXT-5120] Updated wording and formatting; reverted new note
  [ZBXNEXT-5120] Extended support of macro functions