Add memory profiling

[aufdenkampe]

Splitting out from #69, to address the running-out-of-memory issue described by #57 (comment), we need to measure it.

Memory Profiling

We want to also start using memory_profiler to complement our various performance profiling approaches:

• exploring cProfile results (i.e. profile.prof) with SnakeViz
• line_profiler for looking inside functions

Ideally we would run and share these memory and performance profiling tests before and after every PR that addresses performance.

@sjordan29 recently used memory_profiler in:

• Memory management improvements ClearWater-riverine#61