#### Description
During 2s block investigation it turned out that
[ForkAwareTxPool::register_listeners](https://github.com/paritytech/polkadot-sdk/blob/master/substrate/client/transaction-pool/src/fork_aware_txpool/fork_aware_txpool.rs#L1036)
call takes significant amount of time.
```
register_listeners: at HashAndNumber { number: 12, hash: 0xe9a1...0b1d2 } took 200.041933ms
register_listeners: at HashAndNumber { number: 13, hash: 0x5eb8...a87c6 } took 264.487414ms
register_listeners: at HashAndNumber { number: 14, hash: 0x30cb...2e6ec } took 340.525566ms
register_listeners: at HashAndNumber { number: 15, hash: 0x0450...4f05c } took 405.686659ms
register_listeners: at HashAndNumber { number: 16, hash: 0xfa6f...16c20 } took 477.977836ms
register_listeners: at HashAndNumber { number: 17, hash: 0x5474...5d0c1 } took 483.046029ms
register_listeners: at HashAndNumber { number: 18, hash: 0x3ca5...37b78 } took 482.715468ms
register_listeners: at HashAndNumber { number: 19, hash: 0xbfcc...df254 } took 484.206999ms
register_listeners: at HashAndNumber { number: 20, hash: 0xd748...7f027 } took 414.635236ms
register_listeners: at HashAndNumber { number: 21, hash: 0x2baa...f66b5 } took 418.015897ms
register_listeners: at HashAndNumber { number: 22, hash: 0x5f1d...282b5 } took 423.342397ms
register_listeners: at HashAndNumber { number: 23, hash: 0x7a18...f2d03 } took 472.742939ms
register_listeners: at HashAndNumber { number: 24, hash: 0xc381...3fd07 } took 489.625557ms
```

This PR implements the idea outlined in #7071. Instead of having a
separate listener for every transaction in each view, we now use a
single stream of aggregated events per view, with each stream providing
events for all transactions in that view. Each event is represented as a
tuple: (transaction-hash, transaction-status). This significantly reduce
the time required for `maintain`.

#### Review Notes
- single aggregated stream, provided by the individual view delivers
events in form of `(transaction-hash, transaction-status)`,
- `MultiViewListener` now has a task. This task is responsible for:
- polling the stream map (which consists of individual view's aggregated
streams) and the `controller_receiver` which provides side-channel
[commands](https://github.com/paritytech/polkadot-sdk/blob/2b18e080

/substrate/client/transaction-pool/src/fork_aware_txpool/multi_view_listener.rs#L68-L95)
(like `AddView` or `FinalizeTransaction`) sent from the _transaction
pool_.
- dispatching individual transaction statuses and control commands into
the external (created via API, e.g. over RPC) listeners of individual
transactions,
- external listener is responsible for status handling _logic_ (e.g.
deduplication of events, or ignoring some of them) and triggering
statuses to external world (_this was not changed_).
- level of debug messages was adjusted (per-tx messages shall be
_trace_),

Closes #7071

---------

Co-authored-by: Sebastian Kunert <skunert49@gmail.com>