Add webln-v4v form to send boosts via alby browser-extension

[kbondarev]

Closes #36

This PR is still WIP

• Add the V4V form to send boosts
• Customize the style of the form
• Remove hardcoded v4v_tag JSON value and replace using data from episode or from show
• Decide on whether to keep the library script import from CDN (automatic updates) or download it into the repo
• The form has a built in "Accept Terms" view with some text about risks that shows up all before the actual form. At the moment I "disabled" it showing up by setting these attributes on the web component:

  has_accepted_terms="true"
  has_rejected_terms="false"
  

  Showing that view would require some extra work to be done properly:
  • Save the user's answer in a cookie for next time
  • Handle UI elements when user rejects the terms (things on the screen might shift around a little)
• Test it, actually send some sats
• Maybe add a link under the form "Learn more about boosts." leading to the boost page