Given a vector length adn the size of each parition, create a vector which represents those partitions.
create_partitions.Rd
There may be one more partition of size less than the equally divided parts. eg if the vector length is 14 and the desired partitions are size 3, then there will be 4 partitions of length 3 and one of length 2, 1 1 1 2 2 2 3 3 3 4 4 4 5 5.