Support keysend payments in all the tipping features

[bumi]

Is your feature request related to a problem? Please describe.
Currently we support sending tips through lnurl/lightning addresses. People have to have lightning address and add that one to their social media profiles (Youtube, GitHub, Twitter, etc.)
This leaves out users who do not support LNURL.

Describe the solution you'd like
Additionally to LNURL payments we can also support keysend payments. Users then can either provide a lightning address OR a node pubkey in their profiles.
Alby checks if it is a pubkey and uses keysend otherwise it uses the current lnurl pay flow.

We would need to adjust the regex in all the batteries (e.g. https://github.com/getAlby/lightning-browser-extension/blob/master/src/extension/content-script/batteries/GitHub.ts#L21)

In the lightning data we already have the method key which is currently hard-coded to lnurl: https://github.com/getAlby/lightning-browser-extension/blob/master/src/extension/content-script/batteries/GitHub.ts#L42

For keysend data we would probably need to navigate to the keysend screen: https://github.com/getAlby/lightning-browser-extension/blob/master/src/app/screens/Home/index.tsx#L100-L115

(alternatively we could think of a new special tipping screen?)