chore: clean up used libraries

• Remove unused libraries (metrics, JsonSchemaLibrary, RESTinstances)
• Use only robotframework-requests library (modify behavior in API Requests)
• Remove unused function
• Return always response in API Requests
• Remove deprecated Keyword Run Keyword Unless
• Remove duplicated function (Check Status Code Set to)
• Recreate the use of the Output keyword of REST library (pretty print HTTP request and response)