Allows use of multiple style files

[MisterSeajay]

Description

• enable use of multiple style.csv files, with common name format, e.g. style*.csv
• update modules\styles.py to read from, and save to, multiple styles files
• new feature

Screenshots/videos:

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests