Squash of #1502 + moving logo/bootsplash files under branding/Heads
- Move logos and bootsplashes from blobs to branding/Heads/
- Makefile: add support for BRAND_DIR which depends on BRAND_NAME which defaults to Heads if no branding
- Boards coreboot configs: change bootsplash directory to depend on BRAND_DIR (instead of BLOBS_DIR) in bootsplash enabled configs
- Branding/Heads/bootsplash-1024x768.jpg points to branding/Heads/d-wid-ThePlexus_coreboot-linuxboot-heads_background-plain_DonateQrCode.jpg
- xcf file deleted. Original still under #1502 to reuse for modification without recompressing (blobs/heads.xcf)
- CREDITS file created to point to original authors, remixers (Open for details)
- Thanks to: @d-wid for remixing Bing's AI generated Janus logo, @ThePlexus for Qubes Box concept and @ThrillerAtPlay for its matrix background
