Implement NetworksStore

[dlipicar]

There's two lists of networks used across the app

• All Networks (used in the network settings screen or to extract some piece of network-related info for some asset that lives on it)
• "Filtered" Networks list. Includes only the networks currently active (testnet/mainnet mode + isActive setting). Used everywhere we allow the user to select a network from a list (community tokens minting, send/swap/bridge modals, balances, activity, etc.

The 2nd list is generated in several different places, which is error prone. We should probably have a NetworksStore where both are available, and components should just take one (or both) where needed.