Allow scripts to be unscoped / have multiple scopes

Since Zabbix 5.4.0 scripts are currently scoped to be either an action operation, manual host action or manual event action.

In order to be able to use a script in an action, it needs to be scoped to that. But, by doing so you cannot longer use it as host action anymore.

In order use the script both in an action operation and a host operation this would mean that the script needs to be duplicated and scoped accordingly.

It would be nice if:

• Scripts can be unscoped, so they can be used in all available scopes
• or: scripts can be have multiple scopes