Make author style consistent for references

[purva-thakre]

This is related to the changes introduced in #228.

Most of references in articles.bib are not consistent with how they describe some references because they are copied and pasted from arxiv. Some have updated bibtex citations after the preprint was published but some have not which has made the additions in articles.bib inconsistent with each other.

This issue is to make sure:

1. We have a consistent key style: last_name_of_first_author_year_published
2. Some of the keys have the first letter capitalized while others don't. Pick 1 of these options and make this consistent for all keys in articles.bib and books.bib.
3. All authors are added as last name, first name
4. Month is added as a number or month_name or {Month_name}
5. Some of the function docstrings have This function has been adapted/taken from QETLAB without citing the function in QETLAB. Some were cited as a reference in the linked PR as :cite:some_qetlab_func after the ref was added to articles.bib. Make sure all references to QETLAB have been cited correctly.

[purva-thakre]

Closing this as it will be fixed by #228.

Fixed by c5d0a15, c6df2b6, 1db6874, 6280594.