Node options are not fully composable

[AndrewSisley]

Node options cannot safely be appended, as the inner slices overwrite each other instead of appending.

For example, db options are a slice:

type Options struct {
	dbOpts     []db.Option
}

And WithDatabaseOpts overwrites this slice:

func WithDatabaseOpts(opts ...db.Option) NodeOpt {
	return func(o *Options) {
		o.dbOpts = opts
	}
}

This means that one cannot do:

opts := []node.NodeOpt{}
opts = append(opts, WithDatabaseOpts(node.WithUpdateEvents())
...
opts = append(opts, WithDatabaseOpts(db.WithLensPoolSize(lensPoolSize))

As the result would be a db with no update events.

This limits consuming code and risks bugs, both for us (e.g. during test setup), and for any users wishing to use embedded defra.