This commit introduces the following changes to Zenoh-Flow:
1. types used within a Zenoh-Flow application do not have to implement the
   (cumbersome) `ZFData` trait; instead,
2. the types used must be `Send + Sync + 'static`,
3. an Output must know how to serialize the provided type `T` and, respectively,
   an Input must know how to deserialize bytes into `T`.

With these changes, any SerDe compatible data serialization format is supported
as well as, for instance, ProtoBuf.

In terms of API, the major difference is how the Input and Output are obtained:

```rust
input: inputs
    .take("in", |bytes| todo!("Provide your deserializer here"))
    .expect("No input called 'in' found"),

output: outputs
    .take("out", |data| todo!("Provide your serializer here"))
    .expect("No output called 'out' found"),
```

Instead of having the methods `take` and `take_raw` on the Inputs and Outputs,
that give, respectively, the Typed and Raw Input/Output, this commit removes
the `take_raw` variant and introduces builders.

The builders can be turned into the Typed or Raw variant using the corresponding
methods: `build_typed` and `build_raw`.

* feat: reuse buffer when serializing

This commit tries to minimize the number of allocations performed when
serializing data. For this end, the connector and built-in Source now create
internal `Vec<u8>` buffers that are reused whenever a message is serialized.

This change should hopefully improve performance.

* doc: fix typos

Signed-off-by: Julien Loudet <[email protected]>