Ref @andrewkroh's comment here: elastic/integrations#8610 (comment)

Today, there is duplication across integrations that include TLS related fields. In an effort to remove this duplication, we should provide special tls variable types that are "expanded" by Fleet UI to render + provide boilerplate TLS variables without integration maintainers needing to copy/paste TLS configuration across many integrations.

Providing this abstraction will also allow Fleet UI to build a better, more tailored UX around TLS fields that makes use of secrets as appropriate and provides something better than a few text inputs and a YAML textarea.

There are two distinct types of TLS variables exposed in integrations:

• TLS server variables
• TLS client variables

TODO: Add specific examples of each type of variable in an existing integration, clarify exactly which variables should be included in which type.

Rather than define these variables directly, an integration maintainer should be able to define a flag at any level for which vars might exist, e.g.

# my_integration/manifest.yml
policy_templates:
  - name: my_integration
    title: My integration
    include_tls_server_vars: true
    vars:
      - name: bar
        type: text
        ...

Only one of include_tls_server_vars and include_tls_client_vars should be defined at a time in a given manifest.