SAFIR scanners updates

[SomayehSaghamanesh]

Changes in this pull request

Added two models of SAFIR scanners (generic geometry) to stir's scanners list. Added two utilities to convert and trim projections.

Testing performed

STIR-6 build tests were performed successfully without any error. Tests for SAFIR I/II data conversion and image reconstructions were performed successfully.

Related issues

issue #1501

Checklist before requesting a review

• [x] I have performed a self-review of my code
• [] I have added docstrings/doxygen in line with the guidance in the developer guide
• [x] I have implemented unit tests that cover any new or modified functionality (if applicable)
• [x] The code builds and runs on my machine
• [] documentation/release_XXX.md has been updated with any functionality change (if applicable)