[Documentation] How to calculate block hash and block body hash.

It is my understanding that the block hash is the hash of the header of a block;

the hash of the header would be the one to be later included in the next block header as [`prev_hash` field](https://github.com/input-output-hk/cardano-ledger/blob/065f467ab1827549af051a43cb0677cbe7b81d51/eras/babbage/test-suite/cddl-files/babbage.cddl#L30)(null in case the block in question is genesis ?)

the header of a block includes as a field the hash of the body in the [cddl commented with `; merkle triple root`](https://github.com/input-output-hk/cardano-ledger/blob/065f467ab1827549af051a43cb0677cbe7b81d51/eras/babbage/test-suite/cddl-files/babbage.cddl#L35)

in the source the best I could find is [`hashAlonzoTxSeq`](https://github.com/input-output-hk/cardano-ledger/blob/065f467ab1827549af051a43cb0677cbe7b81d51/eras/alonzo/impl/src/Cardano/Ledger/Alonzo/TxSeq.hs#L176)

where it seems the hash of the block body is calculated as something like this

```
hash(
hash( toCbor( bodies ) ) +
hash( toCbor( witnesses ) ) +
hash( toCbor( meatadata ) ) +
hash( toCbor( isValidSet ) )
)
```
( where "`+`" is the concatenation of bytestrings )

### Questions

1) is my understanding of the `block_hash` being different than `block_body_hash` correct?

2) the `Hash` type kinda hides the hash algorithm, is it safe to assume we are talking of `blake2b` with digest of 32 bytes?

3) what is the `; merkle triple root` comment for? I see 4 parts being hashed in `hashAlonzoTxSeq`. are the transactions bodies hashed as a merkle tree? or just as a cbor array of tx bodies?

4) CBOR can represent the same data in many ways, is there a standard encoding for the block elements?