Lowering my Tour bike gearing to MTB gearing
To change from 8 to 10 you will need an upgrade to 10 speed shifters and likely a new derailleur. Almost certainly it would be cheaper to sell the bike and buy another, I would recommend against spending that amount of money on that bike. 

The rear derailleur should be OK, the Altus have a capacity of 43 and max cog size of 34. The front is rated 48MAx, 20 Capacity.  

A 8 or 9 speed 22/32/42(e.g. Shimano M361) crankset would be ideal, but are not that common in better quality sets.  22/30 is a seriously low gear, you will be riding slow enough maintaining balance will be a problem. You can also get a 11/34 8 speed cluster, giving an even lower 22/34 at the expense of wider gear inch gap.