missing details in documentation

[Dimitar Misev]

• WCPS domain© function needs to be documented as non-standard
• document all non-OGC petascope API in one sub-section maybe ​here
• the note about rasql servlet ​here should include a link to ​here
• it should be documented that the rasql servlet supports basic auth ​here
• document the XML exception format returned by petascope on errors, e.g. how rasql errors are split in multiple ExceptionText elements. Maybe in a subsection ​here
• document the rasdaman-specific extensions in the output of WCS GetCapabilities ​here, such as:
  • WCS GetCapabilities response adds the list of axis names for each coverage in rasdaman:axisList elements
• (DM) document prepare_issue_report.sh script ​here