feat: add --sdf option to allow users to use SDF sprite in serve command

[JinIgarashi]

@smellman

Description

closes #175

I tested with the following command to have confirmed SDF sprite is served as localhost

charites serve --sprite-input=test/data/icons --sdf test/data/style.yml

It would be nice if --sdf option is available in build command, but that is not urgent since sprite-one can be directly used to build sprite files, hence I only added this option for serve command

Type of Pull Request

• [x] Adding a feature
• [ ] Fixing a bug
• [ ] Maintaining documents
• [ ] Others ()

Verify the followings

• [x] Code is up-to-date with the main branch
• [x] No build errors after npm run build
• [x] No lint errors after npm run lint
• [x] No errors on using charites help globally
• [x] Make sure all the existing features working well
• [x] Have you added at least one unit test if you are going to add new feature?
• [x] Have you updated documentation?

Refer to CONTRIBUTING.MD for more details.