feat: added required types for LF-672

[H3xept]

Even though the suggested types were

type ToolsResponse = {
  exchanges: Exchange[]
  bridges: Bridge[]
}

type Exchange = {
  tool: ExchangeTools
  chains: number[]
}

I have renamed them to

export type ExternalExchange = {
  tool: ExchangeTools
  chains: number[]
}
export type ExternalBridge = {
  tool: BridgeTool
  chains: number[]
}

to avoid collision with the already declared types Exchange and Bridge.

[mathiasmoeller]

Very nice!