Rename src/ files to match DETELEMENT names

**Is your feature request related to a problem? Please describe.**

There are some mismatches between the file names and names of the detectors. For example, in calorimeters we have:
https://github.com/eic/epic/blob/3b07aea292da030fdf90bf60e00156e2c533d7a8/src/BarrelCalorimeterSciGlass_geo.cpp#L415

**Describe the solution you'd like**
Files should be renamed, maintainers should be notified of the change.

**Describe alternatives you've considered**
Leave names as is.

**Additional context**
This change should not cause any end-user incompatibilities beyond a need to rebase PRs.