[Keymap] Add spidey3 keymap for 75_ansi, and a spidey3 userspace (#8470)

* First cut at Josh Diamond's KBD75 customizations.
Includes:
* My unique keymap with ChromeOS specific keys
* Use RGB underglow to indicate Caps Lock
* Some unicode bindings
* Some changes to make debugging easier

* Updated spidey3 to be applicable to all 75_ansi boards

* Sadly, ChromeOS doesn't pay attention to most consumer codes

* Add mac layer; fix flakeyness in CAPS_LOCK underglow.

* Make layers.json match the keymap (to the extent possible)

* Major cleanup; fix broken debug persistence

* Cleanup some whitespace issues

* Fix incorrect log message.

* Rework layer indication to user RGBLIGHT_LAYERS

* Update layouts/community/75_ansi/spidey3/keymap.c

Co-Authored-By: Drashna Jaelre <drashna@live.com>

* Rename users/spidey3/rgblight.c to layer_rgb.c per suggestion

* Refactor to use set_single_persistant_default_layer().

* Use dprint/f to make logging more elegant.

* Update users/spidey3/config.h

Co-Authored-By: Drashna Jaelre <drashna@live.com>

* Update users/spidey3/config.h

Co-Authored-By: Drashna Jaelre <drashna@live.com>

* Update layouts/community/75_ansi/spidey3/rules.mk

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update users/spidey3/spidey3.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update users/spidey3/layer_rgb.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update users/spidey3/init.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Changes from code review

Co-authored-by: Joshua Diamond <jdiamond@Deep-Thought.local>
Co-authored-by: Drashna Jaelre <drashna@live.com>
Co-authored-by: Ryan <fauxpark@gmail.com>

users/spidey3/unicode.c

@@ -0,0 +1,19 @@
+
+#include "unicode.h"
+
+const uint32_t PROGMEM unicode_map[] = {
+    [BUL1]		= 0x2022, // •
+    [BUL2]		= 0x25E6, // ◦
+    [LARR]		= 0x2190, // ←
+    [RARR]		= 0x2192, // →
+    [ENDASH]	= 0x2013, // –
+    [EMDASH]	= 0x2014, // —
+};
+
+void eeconfig_init_user_unicode(void)
+{
+  // Default to Linux style
+  set_unicode_input_mode(UC_LNX);
+}
+
+