Implement support for ambient providers (like metamask)

[HenryNguyen5]

Ideally, support for ambient providers would include the following non-exhaustive features:

• forced re-routing of requests to the provider in all circumstances
• if any forced re-rerouted requests fail enough for the ambient provider to go offline, so does the entire balancer
• Resolving the ambient provider's current network relative to existing provider configs and future added provider configs
• Have the ambient provider implementation in its own package since it'll be using window #4