Draft PR for Material 3 theming review

[sawankshrma]

To test out different color styles..

1. Delete the src/m3-themes.scss file.
2. run command ng generate @angular/material:m3-theme and give your choice's colors again at each prompts.

for this draft PR The prompts were the following:

Prompt	Input
Primary HEX color	#4CAF50
Secondary color	#757575
Tertiary color	#607D8B
Neutral color	#9E9E9E
Directory	src/
System-level variables?	no
Light, dark, or both?	both