This make the LogBackend `log` method into an async method in
preparation for upcoming changes that will use backpressure from the
connection to delay logging coming from containers.
This also removes unnecessary imageId from the LogMessage type
Change-type: patch
This means that dynamic import statements will emit actual `import`
statements rather than being translated to `require`, the benefit being
that we can now import ES modules via dynamic imports
Change-type: patch
The supervisor uses the following pattern for async module
initialization
```typescript
// module.ts
export const initialised = (async () => {
// do some async initialization
})();
// somewhere else
import * as module from 'module';
async function setup() {
await module.initialise;
}
```
The above pattern means that whenever the module is imported, the
initialisation procedure will be ran, which is an anti-pattern.
This converts any instance of this pattern into a function
```typescript
export const initialised = _.once(async () => {
// do some async initialization
});
```
And anywhere else on the code it replaces the call with a
```typescript
await module.initialised();
```
Change-type: patch
We are refactoring the supervisor test suite into unit tests (for
algorithms an domain model tests) and integration
tests (for interaction with out-of-process dependencies).
This means the current test suite needs to be classified into
these two categories, and fixed whenever possible.
This commit moves the test suite under the `test/legacy` folder, this
folder should be progressively migrated and eventually removed.
Subsequent commits will begin to split these files into unit and
integration whenever possible.
Depends-on: #1996
Change-type: patch
