Remove tech var and bio var variables

[ew367]

Description

This pull request will remove the techVar and bioVar variables from the config.example.r,  checkRconfigFile.r and QC.rmd files and replace them with an overal projVar (project variable).

It will also hard code Sentrix_ID and Sentrix_Position into the QC.rmd doc plots.

Issue ticket number

This pull request is to address issues: #33, #188 and #216

Type of pull request

• [x] Bug fix
• [x] New feature/enhancement
• [ ] Code refactor
• [ ] Documentation update

Checklist

• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have tested my code to check that it is functional
• [ ] I have used linters to check for common sources of errors
• [ ] I have implemented fail safes in my code to account for edge cases
• [ ] I have made the corresponding changes to the documentation

[sof202]

As long as the stuff I've pointed out aren't problems. This is functional and is an improvement over using bioVar and techVar.

[sof202]

This also fixes a problem I had with the define_plot_parameters function where it would output blank vectors if bioVar and techVar were empty. Thank you