documentation

Pull request #732: feature/ZBXNEXT-8087-6.4-D-API feat. ZBXNEXT-1111 (Removal of template nesting & added template versioning).

Merge in WEB/documentation from feature/ZBXNEXT-8087-6.4-D-API to release/6.4

* commit 'a8ff40f9b8dfa9fbc31762c8621c9134e337defd':
  [ZBXNEXT-8087] Removed template nesting (updated "Appendix 2.")
  [ZBXNEXT-8087] Removed template nesting (updated multiple pages)
  [ZBXNEXT-8087] Removed template nesting (updated "Appendix")
  [ZBXNEXT-1111] Template versioning (updated "Template object")
  [ZBXNEXT-1111] Template versioning (updated "Template object")
  [ZBXNEXT-8087] Removed template nesting (updated "template.massremove", "template.massadd")
  [ZBXNEXT-8087] Removed template nesting (updated "template.massupdate")
  [ZBXNEXT-8087] Removed template nesting (updated "template.massadd")
  [ZBXNEXT-8087] Removed template nesting (updated "template.update")
  [ZBXNEXT-8087] Removed template nesting (updated "template.create")
  [ZBXNEXT-8087] Removed template nesting (updated "template.get")
  [ZBXNEXT-8087] Removed template nesting (updated "template.get")
  [ZBXNEXT-8087] Removed template nesting (updated "Method reference" page)