Build a theme generator/picker that simplifies the process

#### Bug, feature request, or proposal:
Feature Request

#### What is the current behavior?
Custom theming angular material is cumbersome.

#### What is the use-case or motivation for changing an existing behavior?
Make it easier to modify theme based on more traditional number color palettes. Designers will often provide 3-6 colors that should encompass most of the application/website, while the material pallets have over a dozen color hues per palette, for a total of well over 50 colors that the app can use. This isn't practical to maintain unless one REALLY cares about each shade. I understand the Ng Material team is just using the official Material colors but in my opinion there is a balance to be struck.

Maybe I'm missing something from the docs but I really would prefer not to do:
$candy-app-primary: mat-palette($mat-indigo); // this palette has over dozen colors to maintain

and instead do
$candy-app-primary: mat-palette(#999); // where 999 is my primary color

And have the material theme generate the variants in some way OR do it like Bootstrap and use scss lightens/darkens mixins where appropriate.

Suggestion:
Incorporate a palette generator of some kind, perhaps using similar logic as used by the material tool.
https://material.io/design/color/the-color-system.html#tools-for-picking-colors

Examinez la documentation actuelle sur le theming de Angular Material et l’utilisation de mat-palette décrite dans l’issue, puis comparez le workflow proposé avec l’outil Material color-system associé. Définissez comment un picker ou un générateur accepterait un petit ensemble de couleurs et produirait des variantes de thème utilisables ; le travail est terminé lorsque ce workflow est spécifié et accompagné d’une documentation appropriée.

Rédigé par le modèle d'indexation à partir du texte de l'issue.