memory leaks

### Environment: (where does this bug occur, have you tried other environments)
- Which branch (often `main` for latest released): `main`

### Steps to reproduce: (give a step by step account of how to trigger the bug)
1. Run `eicrecon` with https://github.com/eic/EICrecon/pull/707
(see [valgrind test](https://github.com/eic/EICrecon/pull/709))

### Expected Result: (what do you expect when you execute the steps above)
No leaks.

### Actual Result: (what do you get when you execute the steps above)
Leaks.

### More notes
- `new` raw pointers with no `delete` is a primary source of leaks
- this may be difficult to resolve, since we need to maintain ROOT streaming of `irt` class objects (ROOT may do the deleting upon write)
- ROOT streaming also prevents us from using smart pointers at this time
- we should address this after v2.0 (merging of `pfrich` branch from #35)