Refactor pallet-state-trie-migration to fungible::* traits (#1801)

## Summary

This PR consolidates `pallet-state-trie-migration` as a part of
https://github.com/paritytech/polkadot-sdk/issues/226 /
https://github.com/paritytech/polkadot-sdk/issues/171:

`pallet-state-trie-migration`:
- [x] replace `Currency` with `fungible` traits
- [x] run benchmarks
- [x] refactor to `DefaultConfig`

`pallet_nicks`:
- [x]  remove

others:
- [x] remove `as Fn*` or `asFun*` stuff based on discussion
[here](https://github.com/paritytech/polkadot-sdk/issues/226#issuecomment-1822861445)

---------

Co-authored-by: Richard Melkonian <35300528+0xmovses@users.noreply.github.com>
Co-authored-by: command-bot <>

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/lib.rs

@@ -243,7 +243,8 @@ impl pallet_balances::Config for Runtime {
 	type FreezeIdentifier = ();
 	// We allow each account to have holds on it from:
 	//   - `NftFractionalization`: 1
-	type MaxHolds = ConstU32<1>;
+	//   - `StateTrieMigration`: 1
+	type MaxHolds = ConstU32<2>;
 	type MaxFreezes = ConstU32<0>;
 }
 
@@ -1674,6 +1675,7 @@ parameter_types! {
 impl pallet_state_trie_migration::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Currency = Balances;
+	type RuntimeHoldReason = RuntimeHoldReason;
 	type SignedDepositPerItem = MigrationSignedDepositPerItem;
 	type SignedDepositBase = MigrationSignedDepositBase;
 	// An origin that can control the whole pallet: should be Root, or a part of your council.