[Feature]Support Elastic Security Exceptions

[approksiu]

Is your feature request related to a problem? Please describe.
Support managing Elastic security exceptions with Terraform, without this feature users are limited to managing only rules-connected exceptions.

Describe the resource you would like to have implemented.
https://www.elastic.co/docs/api/doc/kibana/group/endpoint-security-exceptions-api

Describe the solution you'd like
A resource to manage security exceptions is added, or the existing detection rules resource is extended - please advise on pros and cons.

[marshallmain]

This is important supporting work for #523 - detection rules reference exception lists by ID, exceptions are never stored in the rule objects directly. Exceptions are a major feature of the detection engine so only supporting rules without any exceptions is a big limitation.

The data model we have in Kibana comprises rules, exception lists, and exceptions. Every exception is part of exactly one exception list. Exception lists are just a container object. Each rule can reference one or more exception lists by ID.