documentation

[ZBXNEXT-7469] Added Module API.

Merge in WEB/documentation from feature/ZBXNEXT-7469-6.4-D-API to release/6.4

* commit '7a41f6a5aff6cf393023f17265a2e886b9bb4de6':
  [ZBXNEXT-7469] Updated API request formatting
  [ZBXNEXT-7469] Fixed broken links
  [ZBXNEXT-7469] Updated Module API description #2
  [ZBXNEXT-7469] Updated Module API description
  [ZBXNEXT-7469] Updated links in main "Module" page
  [ZBXNEXT-7469] Updated links in "Module object"
  [ZBXNEXT-7469] Updated main "Module" page
  [ZBXNEXT-7469] Updated "Changes"
  [ZBXNEXT-7469] Updated descriptions, formatting
  [ZBXNEXT-7469] Updated descriptions, formatting
  [ZBXNEXT-7469] Updated formatting, added main "Module" section
  [ZBXNEXT-7469] Created module API section