Show IPFS Actions on DNSLink Sites

[lidel]

cc #689

When we introduced option to opt-out from redirect per site (#687 ) it came with a side effect of removing IPFS context actions.

This PR:

• Adds context actions on DNSLink sites (when redirect is disabled)
  

  This adds context actions such as "Copy IPFS path", "Copy CID", "Pin" to DNSLink websites without redirect.

  It includes refactoring of ipfsPathValidator to expose high level resolvers used in various places by the Companion:

  • resolveToPublicUrl: always return a meaningful, publicly accessible URL that can be accessed without the need of IPFS client.
  • resolveToIpfsPath: return a valid IPFS path that can be accessed with IPFS client.
  • resolveToImmutableIpfsPath: same as resolveToIpfsPath, but the path is always immutable /ipfs/
  • resolveToCid: returns direct CID without anything else

• Adds a bunch of tests
• Tweaks behavior of pin/unpin via browser action menu

  In the past we closed menu after toggling pin status, but now we have a nice visual toggle switch and other uses of the switch do not close the menu, so we unified behavior and toggle action no longer closes the popup menu.

• Works around missing dnslink resolver under js-ipfs

  js-ipfs v0.34 does not support DNSLinks in ipfs*resolve methods yet: Resolving DNSLink Paths: /ipns/<fqdn> js-ipfs#1918
  This temporary workaround detects known errors and falls back to using path from DNSLink cache. It won't be as fresh as original, but at least resolv will work.

[ericronne]

I don't have this running locally, so i can't play with it, but my only note would be to consider applying the colors from #692, to match the browser extension. Thx!

[lidel]

@ericronne yes, it will have correct colors (when #692 is merged)