Distinguish custom payloads and injects with elevated privilege

[EllynBsc]

Use case

Following the feature #1179 and to reproduce a real attack environment, I want to be able to execute a custom payload through a non-system user.

As a second MVP and now that we're able to define a Service Account, we want:

• to distinguish custom Payloads needing elevated privilege to properly work
• to distinguish Injects needing elevated privilege to be properly executed
• the ability to choose level of execution in the Inject form

[jborozco]

Duplicate of #1861