mm: Add BotProblems to BotStatus

[martonp]

This PR adds a BotProblems struct to BotStatus that reports issues that bots are facing. Some problems such as wallet sync and connectivity are checked preemptively while others are reported when errors arise during determining what orders to place and when actually placing them. The preemptive checks are especially important for the Arb bot which additionally confirms that the trading limits allow for an additional trade. Balance deficiencies are also reported in BotProblems.