Demisto-sdk

* Fixed an issue in *generate-docs* where Playbooks and Scripts documentation failed.
* Added a graceful error message when executing the *run" command with a misspelled command.
* Added more informative errors upon failures of the *upload* command.
* format command:
* Added format for json files: IncidentField, IncidentType, IndicatorField, IndicatorType, Layout, Dashboard.
* Added the *-fv --from-version*, *-nv --no-validation* arguments.
* Removed the *-t yml_type* argument, the file type will be inferred.
* Removed the *-g use_git* argument, running format without arguments will run automatically on git diff.
* Fixed an issue in loading playbooks with '=' character.
* Fixed an issue in *validate* failed on deleted README files.

* Added the *max* field to the Playbook schema, allowing to define it in tasks loop.
* Fixed an issue in *validate* where Condition branches checks were case sensitive.

* Added the *slareminder* field to the Playbook schema.
* Added the *common_server*, *demisto_mock* arguments to the *init* command.
* Fixed an issue in *generate-docs* where the general section was not being generated correctly.
* Fixed an issue in *validate* where Incident type validation failed.

* Fixed an issue where the *validate* command did not identify CHANGELOG in packs.
* Added a new command, *id-set* to create the id set - the content dependency tree by file IDs.

* generate-docs command:
* Added the *use_cases*, *permissions*, *command_permissions* and *limitations*.
* Added the *--insecure* argument to support running the script and integration command in Demisto.
* Removed the *-t yml_type* argument, the file type will be inferred.
* The *-o --output* argument is no longer mandatory, default value will be the input file directory.
* Added support for env var: *DEMISTO_SDK_SKIP_VERSION_CHECK*. When set version checks are skipped.
* Fixed an issue in which the CHANGELOG files did not match our scheme.
* Added a validator to verify that there are no hidden integration parameters.
* Fixed an issue where the *validate* command ran on test files.
* Removed the *env-dir* argument from the demisto-sdk.
* README files which are html files will now be skipped in the *validate* command.
* Added support for env var: *DEMISTO_README_VALIDATOR*. When not set the readme validation will not run.

* Added a validator for IncidentTypes (incidenttype-*.json).
* Fixed an issue where the -p flag in the *validate* command was not working.
* Added a validator for README.md files.
* Release notes validator will now run on: incident fields, indicator fields, incident types, dashboard and reputations.
* Fixed an issue where the validator of reputation(Indicator Type) did not check on the details field.
* Fixed an issue where the validator attempted validating non-existing files after deletions or name refactoring.
* Removed the *yml_type* argument in the *split-yml*, *extract-code* commands.
* Removed the *file_type* argument in the *generate-test-playbook* command.
* Fixed the *insecure* argument in *upload*.
* Added the *insecure* argument in *run-playbook*.
* Standardise the *-i --input*, *-o --output* to demisto-sdk commands.