Feature/display backlight control

[finger563]

Description

• Updated display and display_drivers to move backlight_pin and value into display instead of display_drivers
• Add Led compoent as dependency to display component
• Add Led object and initialize it accordingly in display component - backlight pin and value are added to both allocating and non-allocating configs
• Expose set_brightness and get_brightness (range: [0, 1.0]) to the display component.

Motivation and Context

This is used in the esp-box-emu project for esp-cpp/esp-box-emu#40

How has this been tested?

• Building the display_drivers example
• Building and running within the new code for esp-box-emu

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Hardware (schematic, board, system design) change
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• I have updated the .github/workflows/build.yml file to add my new test to the automated cloud build github action.
• All new and existing tests passed.
• My code follows the code style of this project.