lib: scan: Standardize code

- Fix comment format
- Move configurations to kconfig
- Fix undefined function warning
- Remove struct typedefs
- Add missing includes
- Remove hungarian notation

Signed-off-by: Sondre Pettersen <sondre.pettersen@nordicsemi.no>
Co-authored-by: Asil Zogby <asilz@stud.ntnu.no>

Author: sondrep