fix: preload addreses with trailing slash (new multiaddr-to-uri)

[lidel]

This PR switches to latest multiaddr-to-uri and removes code that is no longer needed.

Closes #2333 as a side-effect 👌

Note: multiaddr-to-uri assumes http by default now, which should make it easier and more robust to configure: multiformats/js-multiaddr-to-uri#7

[alanshaw]

Any chance you can quickly send a PR to libp2p-websockets?

⨎ npm ls multiaddr-to-uri
ipfs@0.37.0 /Users/alan/Code/pl/ipfs/js-ipfs
├─┬ libp2p-websockets@0.12.2
│ └── multiaddr-to-uri@4.0.1  deduped
└── multiaddr-to-uri@4.0.1 

[alanshaw]

Tests are passing - bundlesize check is currently failing due to permissions error.