Add BitKit to Adoption Page

[thunderbiscuit]

https://bitkit.to/

They are using ldk-node.

https://github.com/bitcoindevkit/bdk_wallet/pull/257#issuecomment-3265495062

[ovitrif]

Hey, thanks for this 🚀

FYI:

1. We're not yet using ldk-node in production, will be using it in the next major release of the Bitkit app. Current version uses the old' LDK bindings.
2. We're going to use ldk-node exclusively, thus for wallet functionality we rely on its internal BDK instance.

[thunderbiscuit]

Awesome thanks for the extra info!