Add configuration file for eHe3 (#807)

### Briefly, what does this PR introduce?
I would like to run simulation for e He3 scattering, but It seems like
the field was added for this configuration, but the .yml file was not.
So I added the configuration file for eHe3 beams.

### What kind of change does this PR introduce?
- [ ] Bug fix (issue #__)
- [x] New feature (issue #__)
- [ ] Documentation update
- [ ] Other: __

### Please check if this PR fulfills the following:
- [ ] Tests for the changes have been added
- [ ] Documentation has been added / updated
- [ ] Changes have been communicated to collaborators

### Does this PR introduce breaking changes? What changes might users
need to make to their code?
No.

### Does this PR change default behavior?
No.

I hope I am submitting the pull request right this time.. Sorry for the
trouble!

Co-authored-by: Wan Lin <[email protected]>

configurations/craterlake_18x110_He3.yml

@@ -0,0 +1,38 @@
+ebeam: 18
+pbeam: 110_He3
+features:
+  beampipe:
+  tracking:
+    definitions_craterlake:
+    vertex_barrel:
+    silicon_barrel:
+    mpgd_barrel:
+    support_service_craterlake:
+    mpgd_outerbarrel:
+    mpgd_forward_endcap:
+    mpgd_backward_endcap:
+    silicon_disks:
+    tof_barrel:
+    tof_endcap:
+  pid:
+    dirc:
+    pfrich:
+    drich:
+  ecal:
+    forward_homogeneous:
+    forward_insert_homogeneous:
+    bic_default:
+    backward_PbWO4:
+  solenoid:
+  hcal:
+    lfhcal_with_space_for_insert:
+    forward_insert:
+    barrel_gdml:
+    barrel_flux_return:
+    forward_endcap_flux:
+    backward:
+    backward_endcap_flux:
+  far_forward:
+    default:
+  far_backward:
+    default: