rel="manifest" and cookies

[alecmev]

As per spec, cookies aren't being sent with rel="manifest" requests. Currently, the only remedy is to add crossOrigin="use-credentials" to the link tag. I'm able to do that using this snippet:

Favicons.config.html.android["link[rel='manifest'][href$='manifest.json']"] =
  "<link rel='manifest' href='manifest.json' crossOrigin='use-credentials'>"

But this is a dirty hack and will inevitably break in the future. Would you mind having a public option for this? E.g. loadManifestWithCredentials or something like that? I'm not suggesting to make it a default because some may desire to keep the credentials omitted.

[alexander-akait]

@jeremejevs feel free to send a PR

[alecmev]

@evilebottnawi Done: #249