WIP: Add triangular, bcc and hyperkagome lattice

Created by: lgresista

I added the unit cell of the triangular, bcc and hyperkagome lattice. The triangular and bcc lattices where relatively straight forward and the lattice building and symmetry reduction works.

For the hyperkagome lattice I copied the basis and Bravais vectors from Finns frgSolver. I then wrote a small code that transforms the bonds in Finns code into the format that we use and prints them as code. The resulting get_unitcell_hypterkagome() function seems to work. To verify that everything looks correct I checked that all bonds have length 1 and plotted the unitcell including the bonds (hyperkagome_unitcell.pdf). However, two problems arrise. First one can only build the lattice for a size larger than 5, otherwise the code says it is too small to perform the symmetry reduction. Maybe this is the correct behavior, I don't understand the symmetry reduction enough. Second, the symmetry reduction fails and gives an UndefRefError. I did not finded any entries left undefined in the unitcell or the lattice. Dominik, could you look into this?