Add GitHub Actions workflows to measure and report library size changes

[moritz-gross]

see #831
lets see if this already pops up here.

Edit: no it does not, but should be once it exists in main. I added what it'd look like manually below

[moritz-gross]

Linux library size: 0.58 MiB (0.00%)

Revision	Release liblibmathcat.so
Base (307109f)	0.58 MiB (605,448 bytes)
PR (c4c3aeb)	0.58 MiB (605,448 bytes)
Change	0 bytes (0.00%)

Built with default features, Rust 1.96.0, and Ubuntu 24.04. Measurement workflow run.

[moritz-gross]

This first report is posted manually because the PR introduces the workflow_run commenting workflow; GitHub will start running that workflow once it is on the default branch.