setup egress proxy for harvest runner

[rshewitt]

User Story

In order to control outbound traffic from the harvest runner, datagov wants to deploy an egress proxy for the harvest runner

Acceptance Criteria

[ACs should be clearly demoable/verifiable whenever possible. Try specifying them using BDD.]

• GIVEN the traffic we allow/disallow in current harvesting
  WHEN the egress proxy is created and the network policy attached to the harvest runner
  THEN traffic will be managed as expected \

Background

• @FuhuXia and @tdlowden had a discussion on slack about what URLs we can harvest and that led me to looking into how we already do this. after doing some digging it doesn't appear we've created one for the runner. this needs to be replicated across spaces.

Security Considerations (required)

[Any security concerns that might be implicated in the change. "None" is OK, just be explicit here!]

Sketch

• enable egress

[FuhuXia]

The tests looks good, reporting that bad domains are not forbidden.

[FuhuXia]

Two PRs are pending but changes were manually pushed to cloud.gov. Tests are passing after egress enabled.

• add egress to h2.0 apps #5392
• add egress datagov-harvester#351