[xcm] Small enhancements for NetworkExportTable and xcm-builder (#1848)

## Summary

This PR introduces several enhancements.

The current implementation of `NetworkExportTable` lacks remote location
filtering support beyond `NetworkId` lookup. To provide more control and
granularity, it's essential to allow configuration for bridging to
different consensus `NetworkId` while restricting access e.g. to
particular remote parachains.

Additionally, the `StartsWith` and `Equals` and
`StartsWithExplicitGlobalConsensus` helper functions, which are in
active use, are moved to the `xcm-builder` and `frame_support` modules
for better code organization.

Adds a new `LocationWithAssetFilters` filter to enable location-based
and asset-related filtering. This filter is useful for configuring the
`pallet_xcm` filter for
[XcmTeleportFilter](https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/xcm/pallet-xcm/src/lib.rs#L212)
and
[XcmReserveTransferFilter](https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/xcm/pallet-xcm/src/lib.rs#L216)
to restrict specific assets.

Furthermore, the `BridgeMessage` fields are not accessible outside of
`xcm-builder`, limiting the ability to create custom logic dependent on
it.

---------

Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>

bridges/modules/xcm-bridge-hub-router/src/mock.rs

@@ -27,7 +27,7 @@ use sp_runtime::{
 	BuildStorage,
 };
 use xcm::prelude::*;
-use xcm_builder::NetworkExportTable;
+use xcm_builder::{NetworkExportTable, NetworkExportTableItem};
 
 pub type AccountId = u64;
 type Block = frame_system::mocking::MockBlock<TestRuntime>;
@@ -53,8 +53,15 @@ parameter_types! {
 	pub UniversalLocation: InteriorMultiLocation = X2(GlobalConsensus(ThisNetworkId::get()), Parachain(1000));
 	pub SiblingBridgeHubLocation: MultiLocation = ParentThen(X1(Parachain(1002))).into();
 	pub BridgeFeeAsset: AssetId = MultiLocation::parent().into();
-	pub BridgeTable: Vec<(NetworkId, MultiLocation, Option<MultiAsset>)>
-		= vec![(BridgedNetworkId::get(), SiblingBridgeHubLocation::get(), Some((BridgeFeeAsset::get(), BASE_FEE).into()))];
+	pub BridgeTable: Vec<NetworkExportTableItem>
+		= vec![
+			NetworkExportTableItem::new(
+				BridgedNetworkId::get(),
+				None,
+				SiblingBridgeHubLocation::get(),
+				Some((BridgeFeeAsset::get(), BASE_FEE).into())
+			)
+		];
 }
 
 impl frame_system::Config for TestRuntime {