[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>

cumulus/parachains/runtimes/assets/asset-hub-westend/src/xcm_config.rs

@@ -21,9 +21,7 @@ use super::{
 use crate::ForeignAssets;
 use assets_common::{
 	local_and_foreign_assets::MatchesLocalAndForeignAssetsMultiLocation,
-	matching::{
-		FromSiblingParachain, IsForeignConcreteAsset, StartsWith, StartsWithExplicitGlobalConsensus,
-	},
+	matching::{FromSiblingParachain, IsForeignConcreteAsset},
 };
 use frame_support::{
 	match_types, parameter_types,
@@ -45,8 +43,8 @@ use xcm_builder::{
 	EnsureXcmOrigin, FungiblesAdapter, HashedDescription, IsConcrete, LocalMint, NoChecking,
 	ParentAsSuperuser, ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative,
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
-	SovereignSignedViaLocation, TakeWeightCredit, TrailingSetTopicAsId, UsingComponents,
-	WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
+	SovereignSignedViaLocation, StartsWith, StartsWithExplicitGlobalConsensus, TakeWeightCredit,
+	TrailingSetTopicAsId, UsingComponents, WeightInfoBounds, WithComputedOrigin, WithUniqueTopic,
 };
 use xcm_executor::{traits::WithOriginFilter, XcmExecutor};