closes #17

This PR introduces four new endpoints and a new pair of message types

• direct.delete.facts
• direct.delete.problems

Both send a message of the following structure to insights-handler

type DirectDeleteMessage struct {
	Type          string `json:"type"`
	EnvironmentId int    `json:"environmentId"`
	Source        string `json:"source"`
	Service       string `json:"service"`
}

This is used to drive the deletion of insights for an environment - with Service being optional.

Essentially these mirror the deleteProblemsFromSource and deleteFactsFromSource Lagoon core api calls.