Define JobRequest resource

[samsimpson1]

Also fix a load of incorrect package names across the project

This is a first pass. This resource definition needs some adjustments (more validation, comments, etc)

alphagov/govuk-infrastructure#4173

[AP-Hunt]

Is it idiomatic Go to use type aliases to constrain, or at least suggest, valid values?

type Status = string
var (
    StatusRequested Status = "Requested"
    StatusApproved         = "Approved"
    // ...
)

[samsimpson1]

The validation here ends up in the CRD, so you'd need to define the set of valid options twice. I'm going to leave it as is for now, and if creating a type alias makes it easier to implement the actual operator logic, it could be added later