[Feature] change `EvmFactory` trait to let implementers use a stricter trait for the generic `DB` to give to the EVM

### Describe the feature you would like

Right now the `EvmFactory` trait in the `alloy-evm` crate has an associated type called `Evm` that has a generic `DB: alloy_evm::Database`.

https://github.com/alloy-rs/evm/blob/224bf74d78c3d901e3855e7932d1d8f82d75f553/crates/evm/src/evm.rs#L197

This makes it impossible in the concrete implementation to use a trait that is stricter than the `alloy_evm::Database` trait because of how Rust compiler works with generic defined on associated types (instead of the generic being defined in the trait itself - something like `pub trait EvmFactory`.

Do you think it could make sense to change the trait such that it lets implementers use a stricter (meaning it's at least `Database`, but it may have additional requirements such as thread safety `Send + Sync` or clonable `Clone`) trait on the DB.

I'm down to help here if you give me some guidance and find the proposal appealing.

### Additional context

_No response_