[Performance] At 4k links, rendering takes perceivable time.

[NaimKabir]

It's noticeable when the extension is loading in the current set of links in order to render it.

We should start by rendering just the first few hundred and then loading up the rest into memory, using cached knowledge of used IDs.

• Upstream change to allow this merged here. Not yet available in Chrome :(

[NaimKabir]

Working on this here: #27