[Library Manager] add slight_* libs

[s-light]

please add my libraries

• https://github.com/s-light/slight_Fade
• https://github.com/s-light/slight_ButtonInput
• https://github.com/s-light/slight_RotaryEncoder
• https://github.com/s-light/slight_DebugMenu
• https://github.com/s-light/slight_TLC5957
• https://github.com/s-light/slight_FDC1004
• https://github.com/s-light/slight_LiquidCrystalDummy

to the library index.

thanks :-)
sunny greetings
stefan

[cmaglie]

Done.

[s-light]

Thanks! :-)