Simple excel engine - supports a small subset of functions currently

Project idea inspired by: https://www.youtube.com/watch?v=HCAgvKQDJng

Expects input of the form

1|2|3|4
=sum(a1:d1) * a2 / a3|4|5|6

This will evaluate to

1|2|3|4
6|4|5|6

Future extensions

• [] Implement additional function types
• [] Reduce the amount of clone -> potentially bad choice of bigdecimal
• [] Tidy up some of the code