Updated the documentation with:
* Core Actions
* Cloud Notification Actions
* Persistence Extensions
* Ephemeris Actions
* Types and Units
Instead of the single "imports", the default scope
(openhab-core/DefaultScriptScopeProvider.java) is used.
It's imported as `openhab`, services are under `openhab.service`.
As the helper library is on the way (openhab/openhab-js):
* Added note about console.log and logging in general.
* Added note that the lib is on the way.
Signed-off-by: Florian Hotze <florianh_dev@icloud.com>
