Introduce Wavelet Matrix

[Cydhra]

Merge the Wavelet Matrix (#4) into main. This Pull Request is tracking the progress.

Things left to do:

• [x] write tests for all convenience functions to make sure no oversights are left
• [x] write the quantile function to allow some summary statistics on the encoded sequence
• [x] mirror all rank/select functions to use a u64 in place of the BitVec parameter for convenient access with less than 64 bit alphabets
• [x] implement an iterator over the sequence
• [x] implement sequential prefix counting as a constructor (https://doi.org/10.1145/3457197)
• ~implement FromIterator~
• [x] finalize the decisions when to return None in checked rank/select functions, and when to panic
• [x] Add examples to doc comments
• [x] Add sorted iterator
• [x] predecessor and successor functions