feat: support keysend in lightning meta tag

[bumi]

Describe the changes you have made in this PR

This adds support for keysend payments with the lightning meta tag.
I also think that the meta tag should follow a similar naming and usage as the podcast:value tag.

the meta tag can now define:

• method: lnurl or keysend
• address: the recipient (lnurl/lightning address or node key)
• customKey/customValue: custom record for keysend

ToDo:

• update meta tag spec
• remove passing data by search params (see comments in Support all LNURLs from the send popup-screen #1216)

Link this PR to an issue

#792

Type of change (Remove other not matching type)

• feat: New feature (non-breaking change which adds functionality)

How has this been tested?

example meta tag:

<meta name="lightning" content="method=keysend; address=030a58b8653d32b99200a2334cfe913e51dc7d155aa0116c176657a4f1722677a3; customKey=696969; customValue=3wQCCrfOAMYNzOh1sL05" />

Checklist

• My code follows the style guidelines of this project and performed a self-review of my own code
• New and existing tests pass locally with my changes
• I checked if I need to make corresponding changes to the documentation (and made those changes if needed)

[bumi]

How do I do this in proper TS: https://github.com/getAlby/lightning-browser-extension/pull/1223/files#diff-cdee507dd9e4243d8b288907c7c1d3924972f7c47c0a08b5c3d16fe079efad30R16

[github-actions]

Build files:

• Firefox
• Chrome

[im-adithya]

How do I do this in proper TS: https://github.com/getAlby/lightning-browser-extension/pull/1223/files#diff-cdee507dd9e4243d8b288907c7c1d3924972f7c47c0a08b5c3d16fe079efad30R16

Not quite sure, but this can be one way to avoid errors:

  const obj: Record<string, string>= {};
           ------------------------
  tokens.forEach((t) => {
    const kv = t.split("=").map((e) => e.trim());
    obj[kv[0]] = kv[1];
  });
  return obj as unknown as Battery;
             -----------

[escapedcat]

return obj as unknown as Battery;

I guess this would be a ok workaround for now till we took care of how to handle transforming URL-params into matching types later.

[bumi]

I guess this would be a ok workaround for now till we took care of how to handle transforming URL-params into matching types later.

those are actually unrelated of the URL-params.
this data is just loaded and used in the Home screen to show the "Send sats" button.