Necessary fixes

Introduces necessary fixes:

1. renamed to plob bound (which is the correct name and avoids confusion, old name is suuper unclear)

2. apply sifting factor of 1/2 because we don't sample basis randomly

3. removes normalized SKR in order to remove hardware dependence. Normalization can now be done in plotting

4. changed the degree of the poly_fit to rate to 5 (rate does not behave linearly)