feat: enable customising delegated http router

[2color]

Description

Allow passing delegated routing client options, e.g. IPIP-484 filters, to the delegated HTTP router.

Notes & open questions

• Should we also set default filters as proposed in feat: enable filtering in delegated routing client #651 to the delegated HTTP router? If so, should we follow the same defaults as feat: enable filtering in delegated routing client #651 (with different defaults for browser vs. node.js)?

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

[SgtPooki]

we probably also need to update the createHelia functions to support passing these through right?

[2color]

For the normal helia, i .e. HeliaP2P, we don't even instantitate the delegatedHTTPRouter, so not relevant:

helia/packages/helia/src/index.ts

Lines 115 to 130 in e5c03bd

	const helia = new HeliaP2P({
	...init,
	libp2p,
	datastore,
	blockstore,
	blockBrokers: init.blockBrokers ?? [
	trustlessGateway(),
	bitswap()
	],
	routers: init.routers ?? [
	libp2pRouting(libp2p),
	httpGatewayRouting()
	],
	metrics: libp2p.metrics
	})

For @helia/http, we do use the delegatedHTTPRouter: https://github.com/ipfs/helia/blob/f904041bdd2643fabd204485825d4761fc44a83f/packages/http/src/index.ts/#L79-L82

But if you want to cutsomise the delegatedHTTPRouter options, you can just instantiate it yourself and pass it in via init.router (a bit like how we do it in the example)