feat(pallet-assets-registry): simplify asset id generation

[mina86]

No need to allocate a Vec or deal with infallible unwraps. Just use
plain bit manipulation to generate the asset id.

Required for merge:

• pr-workflow-check / draft-release-check is ✅ success
• Other rules GitHub shows you, or can be read in configuration

Makes review faster:

• PR title is my best effort to provide summary of changes and has clear text to be part of release notes
• I marked PR by misc label if it should not be in release notes
• Linked Zenhub/Github/Slack/etc reference if one exists
• I was clear on what type of deployment required to release my changes (node, runtime, contract, indexer, on chain operation, frontend, infrastructure) if any in PR title or description
• Added reviewer into Reviewers
• I tagged(@) or used other form of notification of one person who I think can handle best review of this PR
• I have proved that PR has no general regressions of relevant features and processes required to release into production
• Any dependency updates made, was done according guides from relevant dependency
• Clicking all checkboxes
• Adding detailed description of changes when it feels appropriate (for example when PR is big)

[github-actions]

Pull reviewers stats

Stats of the last 30 days for composable:

	User	Total reviews	Time to review	Total comments
	dzmitry-lahoda	24	12h 53m	19
	blasrodri	17	1h 23m	11
	RustNinja	16	1h 11m	2
	mina86	15	1d 37m	82
	kkast	12	3h 53m	7
	vmarkushin	3	7h	2
	JafarAz	3	9h 25m	0
	0xBrainjar2	1	3d 17h 35m	6

[github-actions]

# run Composable node
nix run "github:ComposableFi/composable/refs/pull/4067/merge" --allow-import-from-derivation --extra-experimental-features "flakes nix-command" --no-sandbox --accept-flake-config --option sandbox relaxed

# run local Picasso DevNet (for CosmWasm development)
nix run "github:ComposableFi/composable/refs/pull/4067/merge#devnet-picasso" --allow-import-from-derivation --extra-experimental-features "flakes nix-command" --no-sandbox --accept-flake-config --option sandbox relaxed 

# CosmWasm on Substrate CLI tool
nix run "github:ComposableFi/composable/refs/pull/4067/merge#ccw" --allow-import-from-derivation --extra-experimental-features "flakes nix-command" --no-sandbox --accept-flake-config --option sandbox relaxed 

# run cross chain devnet with Dotsama and Cosmos nodes 
nix run "github:ComposableFi/composable/refs/pull/4067/merge#devnet-xc-fresh" --allow-import-from-derivation --extra-experimental-features "flakes nix-command" --no-sandbox --accept-flake-config --option sandbox relaxed 
# or same with docker
nix build "github:ComposableFi/composable/refs/pull/4067/merge#devnet-xc-image" --allow-import-from-derivation --extra-experimental-features "flakes nix-command" --no-sandbox --accept-flake-config --option sandbox relaxed \
&& docker load --input result && docker run -it --entrypoint bash devnet-xc:latest -c /bin/devnet-xc-fresh 

About nix

[dzmitry-lahoda]

oh, forgot about it.

[blasrodri]

Can you add some docs? As in how the layout works, and therefore why these operations are correct?