Is your feature request related to a problem? Please describe.
The Create Space API in Kibana allows specifying a solution option to configure the space UI.

Describe the solution you'd like
Support for this option should be included in the elasticsearch_kibana_space resource

Describe alternatives you've considered
When using Elastic Cloud hosted there doesn't seem to be another way to configure this via Terraform.

Plan

• Add support for setting the solution field in the API client (libs/go-kibana-rest/kbapi/api.kibana_spaces.go)
• Support the new solution attribute in the Resource (internal/kibana/space.go)
  • Ensure the new attribute is validated, valid options are security, oblt, es, or classic.
• Support the new solution attribute in the Data Source (internal/kibana/spaces)
• Update the acceptance tests for both the Resource and Data Source
• Update the documentation with make docs-generate.
• Add an entry to CHANGELOG.md for the PR.