Tasks: Create Internal Tasks User

[nik9000]

As a follow up to #35667 I'd like to create an internal tasks user so tasks don't have to use the XPackUser that has permission for a ton of stuff. I'm already working on a first step for this but I wanted to create this to make sure that it doesn't fall through the cracks.

[elasticmachine]

Pinging @elastic/es-distributed

[henningandersen]

@nik9000 do you still want to provide a change for this?

[elasticmachine]

Pinging @elastic/es-security

[tlrx]

We discussed this is small group today and we think this issue is now obsolete now we have a system user for internal action.

I'm going to close this as part of our spring cleaning duty but feel free to reopen if our assumption is wrong.

[tvernum]

This might not be a priority, but I don't think we've made any changes that would resolve this issue since @nik9000 raised it.
See:

elasticsearch/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authz/AuthorizationUtils.java

Lines 141 to 142 in 44fa734

	case TASKS_ORIGIN: // TODO use a more limited user for tasks
	securityContext.executeAsInternalUser(XPackUser.INSTANCE, version, consumer);

[tlrx]

Thanks for the precision Tim. I'm tempted to leave this issue closed given it received very small attention in the last 4 years.