Merge #202

202: Add a tool that prints information on the sizes of the examples. r=jrvanwhy a=jrvanwhy

The tool prints the size of .bss, .data, and .text (which currently includes .rodata). I tried to adjust the linker script to separate out .rodata, but unfortunately that caused RISC-V apps to fault. I'll take care of that in a later PR, when I refactor the entry point and layout script.

I intend to develop a GitHub Action similar to tock/tock's that runs print-sizes on incoming PRs and displays the diff relative to the PR's target branch.

Co-authored-by: Johnathan Van Why <jrvanwhy@google.com>