Add borders and shaders about retrodeck HOT 6 CLOSED

The work can be followed here: https://trello.com/b/Hwy5jdS0/retrodeck-graphics

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Implementation idea:

• borders will be enabled by default in retroarch.cfg
• a tool will be created to disable/enable the borders, this tool will operate with a sed on retroarch.cfg to edit the border option

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Another way could be to include this: https://www.libretro.com/index.php/retroarch-introducing-the-mega-bezel/

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This collection of borders is available under the MIT license and seems pretty nice to me personally.

If the following settings are configured in retroarch.cfg (I believe these are defaults anyway), per-core bezels can be configured and used:

auto_overrides_enable = "false"
And
game_specific_options = "true"

and then per-core settings can be set in

<retroarch root>/config/<core name>/<core name>.cfg

For example, for Snes9x, the file would be in

<retroarch root>/config/Snes9x/Snes9x.cfg

and would contain the line

input_overlay = "<path to SNES9x overlay cfg file>"

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• Added borders: #128
• Shaders
• Script to enable/disable them

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Dupe

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