Refactored mass technology-factor: removed global, added per-stabilizer

Description

Removed the technology factor for FLOPS mass calculations for the empennage as a global parameter and added the parameter to each individual stabilizer element in the config. Adapted the TailElement-Class to read in the factor.

Related Issue(s)

• Closes #142

Developer Checklist

• Code has been tested locally and/or in pipeline.
• Merge conflicts resolved with the target branch.