Refactor steno and add STENO_PROTOCOL = [all|txbolt|geminipr] (#17065)

* Refactor steno into STENO_ENABLE_[ALL|GEMINI|BOLT]

* Update stenography documentation

* STENO_ENABLE_TXBOLT → STENO_ENABLE_BOLT

TXBOLT is a better name but BOLT is more consistent with the
pre-existing TX Bolt related constants, which all drop the "TX " prefix

* Comments

* STENO_ENABLE_[GEMINI|BOLT|ALL] → STENO_PROTOCOL = [geminipr|txbolt|all]

* Add note on lacking V-USB support

* Clear chord at the end of the switch(mode){send_steno_chord} block

* Return true if NOEVENT

* update_chord_xxx → add_xxx_key_to_chord

* Enable the defines for all the protocols if STENO_PROTOCOL = all

* Mention how to use `steno_set_mode`

* Set the default steno protocol to "all"

This is done so that existing keymaps invoking `steno_set_mode` don't
all suddenly break

* Add data driver equivalents for stenography feature

* Document format of serial steno packets

(Thanks dnaq)

* Add missing comma

data/schemas/keyboard.jsonschema

@@ -361,6 +361,17 @@
                 }
             }
         },
+        "stenography": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+                "enabled": {"type": "boolean"},
+                "protocol": {
+                    "type": "string",
+                    "enum": ["all", "geminipr", "txbolt"]
+                }
+            }
+        },
         "split": {
             "type": "object",
             "additionalProperties": false,