Runtime lifecycle APIs

Just thinking ahead a little.

The runtime should provide lifecycle hooks which can be imported by adaptors (and jobs, why not).

Ie, language-postgres will want to do this:

import { onStart, onEnd } from '@openfn/runtime

onStart(() => connect(state.data.configuration) );
onEnd(() => tearDown());

This is a sketch of the interface:

// Run a function when the pipeline starts (a pre or init step)
export onStart(fn(state: any) => state): void;

// Run a function when the pipeline ends (a post or final step)
export onStart(fn(state: any) => state): void;

// Run a function before each job
// Maybe not useful for adaptors but probably useful for runtime managers!
// Maybe this should take the operation, or some metadata about it, as an argument
export beforeEach(fn(state: any) => state): void;

export afterEach(fn(state: any) => state): void;

Do we want the API to be registerCallback or onEvent or hooks.onStart ?

Do we want pre and post semantics instead of start and end?

An alternative API would be like:

type HookStage = 'start' | 'end' | 'beforeEach' | 'afterEach'

addHook(when: HookStage, fn: Operation)

The issue names no implementation files or tests. Start by locating the runtime entry points used by adaptors and jobs, then resolve the proposed start, end, beforeEach, and afterEach semantics and API shape; done means an agreed lifecycle-hook interface with coverage for its behavior.