add discover_scripts service

[malinovsku]

The discover_scripts method has been added for creating services, similar to native integration, but with some additions, optional constants FIELDS, DESCRIPTION, NAME for service parameters are expected in the script, an example below.
With this feature, it is easier to share scripts and services are clear to run.
The revision does not affect the previous functionality in any way, but only complements

NAME = "test"
DESCRIPTION = "new script"
FIELDS = {"url": {"required": True, "selector": {"template": ""}}}

[malinovsku]

pr updated for version 1.0.2