Support IPFS gateway method first on Android

[bbondy]

Let's add support for IPFS via gateway to Android.

We would show this page on the first IPFS load:
#13655

But without the local node option to start.

[lidel]

👍 (cc @autonome)
Ubiquitous support for resolution of ipfs:// and ipns:// URIs (even if its only via a customizable gateway) is very important for us

[bbondy]

Re-opening because of a warning causing an error on Android. I'll fix then re-land.

[stephendonner]

Verified PASSED using Brave 1.24.76, Chromium 90.0.4430.85 on Android 9, Google Pixel XL, arm64.

Steps:

1. new profile/install
2. loaded ipns://brantly.eth
3. confirmed I got the interstitial page
4. tapped on Use public gateway
5. confirmed the page loaded after a brief DNS lookup (and error page, expected for now - we've fixed that on desktop, I believe)
6. new profile/install (again)
7. load ipfs://bafybeiemxf5abjwjbikoz4mc3a3dla6ual3jsgpdr4cjr3oz3evfyavhwq/wiki/Vincent_van_Gogh.html
8. tapped on Use public gateway
9. confirmed the page loaded after a brief DNS lookup (and error page, expected for now - we've fixed that on desktop, I believe)

example	example	example	example

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Verification passed on Samsung Tab A with Android 10 running 1.24.81 x64 build

• Verified when a ipns:// or ipfs:// URI is loaded shows the interstitial page
• Verified using public gateway loads the page correctly using public gateway
• Verified when IPFS public gateway setting is disabled in setting, page fails to load

Interstitial Page	ipns://	Error page when public gateway disabled

Interstitial Page	ipfs://	Error page when public gateway disabled