[FEAT][TEST] Adding relevant variables for flight model

[tillmrtz]

This pull request resolves #87

Description:

• In order to run the flight model, important variables like C_VBD, mass and volmax of the glider are needed
• Two functions were added that extract the variables form a list of potential variables and adds them to the OG1 dataset

Checklist:

• I have followed the coding conventions.
• I have updated or added tests to cover my changes.
• I have updated the documentation if needed.
• I have run pytest to check that all tests pass.
• I have run pre-commit run --all-files to lint and format the code.

Link any related issues, pull requests, or discussions:

• Related to Add glider metadata needed for flight model in OG1 format #87

[mari-lage]

Looks good :)

[mari-lage]

Now it should work

[mari-lage]

Maybe this works now...