[Sim] Combine integer formatting ops into one op

@fzi-hielscher I was wondering what your thoughts are on maybe combining the integer formatting operations `sim.fmt.hex`, `sim.fmt.bin`, and `sim.fmt.dec` into a single `sim.fmt.int` operation. The Moore dialect wants to lower to these ops, and there are additional formatting options (width, alignment, zero/space padding) that apply to each of these ops. If we made the integer radix a parameter on the op, we might only have to add these formatting options to a single op. WDYT?

Start with the sim.fmt.hex, sim.fmt.bin, and sim.fmt.dec operations and the Moore dialect lowering mentioned in the issue. Determine whether a radix-parameterized sim.fmt.int operation should consolidate the shared width, alignment, and padding options; done means the design is agreed and the affected lowering paths are identified.

Written by the indexing model from the issue text.