docs: add security policy

Future-based syncing module

It's outdated and the interface has vastly changed. Removed temporarily to add
it back later.

Pin it to BeaconBlock. The methods and structs are really specific to beacon
setup, so there's nearly no use to generalize this.

Initial integration of gossipsub networking stack

This adopts the full networking stack from lighthouse

Code is adopted from lighthouse, which is licensed under Apache-2. Unfortunately
because the dependencies we use are different, it's not possible to directly
depend on upstream.

So that we're on a version that supports gossipsub, thanks to lighthouse.

This copies blockchain-network-libp2p crate as the foundation to continue to
build upon.

beacon-wasm: use the builtin serde feature provided by wasm-bindgen

beacon, beacon-wasm: fix incorrect example block and remove f64 parsing for uint

wasm: fix U1099511627776 exceeding u32 limit

dep: update bm-le to 0.10