Upgrade zapthreads

[franzaps]

Finally, new version of zapthreads!

• Biggest rewrite yet, local storage is more performant and there's a fallback for browser windows with no IndexedDB (like private Firefox)
• Comments on highlights are now shown
• Most importantly, replies are no longer done to an a tag but to an actual ID (see discussion Update NIP-10 including definitions for "a" tags nostr-protocol/nips#809 (comment)) which means no more out of context comments in other apps!
• Added a notice if a comment does not have a parent - see fiatjaf's PR here If the reply has an e tag that doesn't match the current id of the replaceable event, display a notice franzaps/zapthreads#35

@verbiricha