clean up refs in proper bib format

[sunt05]

• [x] bib records:
  • [x] Stretton et al.2022: Modelling vertically resolved shortwave radiation in urban areas: evaluation of SPARTACUS-Urban. Boundary Layer Meteorology
  • [x] Stretton et al. in prep: Characterising the vertical structure of urban buildings for use in atmospheric models.
• [x] add citations in the text for the following refs
  • [x] Berrizbeitia et al (2020)
  • [x] Oke et al. (2017) urban climates book
  • [x] Stephens (2012)
  • [x] Stretton et al. (2022)
  • [x] Stretton et al. in prep

[sunt05]

@LewisB7 please ignore these: I find these are irrelevant to your original doc.