Refactor: Restructure event and rename context

This commit introduces two key changes to the Tracee event structure:

- Renames the `context` field to `workload` to provide a more specific and
  clear description of the execution environment.
- Moves the `triggeredBy` field from the `data` section to the root of the
  event structure. This ensures the `data` section is strictly defined by the
  event-specific schema, improving consistency and clarity.

These changes constitute a breaking change to the API. However, as `traceectl`
is not yet merged, it is acceptable to introduce this breaking change now to
avoid future complications.

commit: 0757020 (main), cherry-pick

Author: yanivagman