kedro-telemetry: update telemetry docs for opt-out model

[DimedS]

Description

Following the transition to an opt-out model for telemetry with #715, the telemetry documentation should be revised accordingly. This includes updates to the following resources:

• Kedro Telemetry Documentation
• Kedro Telemetry Plugin Readme.md
  The revisions should also provide comprehensive information about all the available methods to disable telemetry, as outlined in kedro-telemetry: Introduce environment variables for disabling telemetry and revise disabling methods #728.