Fix crash when creating a feeder bay using an empty dataframe

[geofjamg]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [x] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem?

No

What kind of change does this PR introduce?

Bug fix

What is the current behavior?

When creating for instance a load feeder bay with an empty load dataframe, we get a crash (segv).

What is the new behavior (if this is a feature change)? A check has been added to avoir the crash.

Does this PR introduce a breaking change or deprecate an API?

• [ ] Yes
• [ ] No

If yes, please check if the following requirements are fulfilled

• [ ] The Breaking Change or Deprecated label has been added
• [ ] The migration steps are described in the following section

What changes might users need to make in their application due to this PR? (migration steps)

Other information: