feat(Util): add SweptCollection for auto sweeping of caches

[ckohen]

Please describe the changes this PR makes and why it should be merged:

⚠️ Updates Collection dep, including breaking changers
⚠️ Updates node requirement to 14.6.0 for Finalizers and WeakRef

Eslint config has been updated to target es2021 as well.

Adds SweptCollection (mainly for use with threads but has other uses). This can replace Client#sweepMessages, however with the loss of debug events, which is why it was not removed.

Other breaking change is the change in ThreadManager, to automatically sweep archived threads older than 4 hours every hour (default sweep settings)

I'm open to changes for these defaults, kinda just picked them at random.

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating
• This PR changes the library's interface (methods or parameters added)
• This PR includes breaking changes (methods removed or renamed, parameters moved or removed)

[kyranet]

Also, just one tiny question... we need to access to the Client instance, in an object that is used to build the instance itself, do you have an example on how to use this?

[1Computer1]

From the discord, my suggestions on the interface:

• Remove client related stuff after refactor: remove timer utilities from Client #6113.

• More general interface like so:

export class SweptCollection<K, V> extends Collection<K, V> {
  public constructor(options: SweptCollectionOptions<K, V>, iterable?: Iterable<readonly [K, V]>);
  public maxSize: number;
  public shouldKeep: ((value: V) => boolean) | null;
  public sweepInterval: number | null;
  public sweepFilter: (() => (value: V) => boolean) | null;
}

export interface SweptCollectionOptions<K, V> {
  maxSize?: number;
  shouldKeep?: (value: V) => boolean;
  sweepInterval?: number;
  sweepFilter?: () => (value: V) => boolean;
}

Usage example:

new SweptCollection({
  sweepFilter: () => {
    const now = Date.now();
    return (t) => {
      if (!t.createdTimestamp) return false;
      if (!t.archived) return false;
      return now - t.createdTimestamp > lifetimeMs;
    };
  }
});

// Can make some utilities for users:
new SweptCollection({
  sweepFilter: SweptCollection.filterByLifetime({
    maxLifetime: lifetimeMs,
    getCreationTime: t => t.createdTimestamp,
    shouldKeep: t => !t.archived
  })
});

• Possibly remove letting users keep items at max cache due to the fact that set is now O(n).

• Too many cacheWiths now, I think it's best to do this perhaps:

public static cacheByManager(fs: Record<string, () => Collection<any, any>>): CacheFactory { ... }

[ckohen]

Did most of what comp suggested, couple of name changes to make it clearer what these things do.

The only thing I didn't touch:

• Too many cacheWiths now, I think it's best to do this perhaps:

public static cacheByManager(fs: Record<string, () => Collection<any, any>>): CacheFactory { ... }

What's the point in this, this seems harder than just implementing your own makeCache function. In fact, the only difference is that you're not building the default case.

Stale

Stale