Include batch features in the "payments" app docs

[razgraf]

Update https://docs.sablier.com/apps/features/payments to include details and pictures for

• Multi-top-up through the batched deposits (highlight suggestions for topping up for 30 days)
• Save for later through batch search

[PaulRBerg]

Many Flow users have continued to ask about topping up multiple streams .. @smol-ninja could you work on this task this week, please?

[smol-ninja]

Documented in #283. Tried several iterations for heading and content and ended up with (1) Top up multiple streams (2) Save URL and top up later. Since, it was hard to show the feature through a single image, I used gif to explain how one can top up multiple streams at once. Used 30 days example for demo.

Previews

1. https://docs-ceqpqac5q-sablier.vercel.app/apps/features/payments#top-up-multiple-streams
2. https://docs-ceqpqac5q-sablier.vercel.app/apps/features/payments#save-url-and-top-up-later

Also, placed it "Preview any stream" because I think its more important than NFT and all other features below it.

Let me know what you think.