Support API entered as URL with Basic Auth

[lidel]

Support API as URL with Basic Auth was introduced in ipfs-inactive/ipfs-redux-bundle#28
Deprecating ipfs-redux-bundle and switching to ipfs-provider (#1563) introduced a small regression: it is no longer possible to connect to API defined as URL with basic auth credentials. Entering URL and pressing Submit does nothing:

We need to restore this feature in webui (and release new ipfs-provider, if needed).

Ref.

• Simple proxy that adds basic auth to existing API can be found in feat: allow urls with authentication ipfs-inactive/ipfs-redux-bundle#28 (review) (useful for testing this)

[jessicaschilling]

We should also add some basic guidance to the running text: something like "if your API isn't on localhost, you'll need to include your authorization credentials, e.g. blahblah".

[lidel]

Quick update:

As suspected, this was broken, but should be easy to fix: http client expects us to create explicit Authorization: Basic ... header, so we will do just that.

I'll prepare PR which:

• accepts URLs with user/password
• converts it to options object accepted by ipfs-http-client constructor
• adds support for advanced options object (Status and Settings pages)
• adds e2e tests which confirm basic auth works