[v8] Update Node support to Node 14+

[mydea]

In v8, we want to update the supported Node versions.

Currently, we support Node 8+.

In the coming major v8, we want to raise this to Node 14+.

To use Node with ESM, you'll need Node 18+.

Open questions

Should we raise this more? E.g. support Node 16+? Personally I'd vote for 14+ (as that is already a large jump) and then raise it again in the next major, which does not need to be 18 months out again, necessarily.