refactor(docs): Convert the keymaps section into a base folder (#2430)

Co-authored-by: Cem Aksoylar <caksoylar@users.noreply.github.com>

docs/docs/keymaps/behaviors/layers.md

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+---
+title: Layer Behaviors
+sidebar_label: Layers
+---
+
+## Summary
+
+Often, you may want a certain key position to alter which layers are enabled, change the default layer, etc.
+Some of those behaviors are still in the works; the ones that are working now are documented here.
+
+:::note
+Multiple layers can be active at the same time and activating a layer will not deactivate layers higher up in the "layer stack". See [Layers](../index.mdx#layers) for more information.
+:::
+
+## Defines to Refer to Layers
+
+When working with layers, you may have several different key positions with bindings that enable/disable those layers.
+To make it easier to refer to those layers in your key bindings, and to change which layers are where later, you can
+add a set of `#define`s at the top of your keymap file, and use those layer in your keymap.
+
+For example, if you have three layers, you can add the following to the top of your keymap:
+
+```dts
+#define DEFAULT 0
+#define LOWER   1
+#define RAISE   2
+```
+
+This allows you to use those defines, e.g. `LOWER` later in your keymap.
+
+## Momentary Layer
+
+The "momentary layer" behavior enables a layer while a certain key is pressed. Immediately upon
+activation of the key, the layer is enabled, and immediately upon release of the key, the layer is disabled
+again.
+
+### Behavior Binding
+
+- Reference: `&mo`
+- Parameter: The layer number to enable while held, e.g. `1`
+
+Example:
+
+```dts
+&mo LOWER
+```
+
+## Layer-Tap
+
+The "layer-tap" behavior enables a layer when a key is held, and outputs a [keypress](key-press.md) when the key is only tapped for a short time.
+
+### Behavior Binding
+
+- Reference: `&lt`
+- Parameter: The layer number to enable while held, e.g. `1`
+- Parameter: The keycode to send when tapped, e.g. `A`
+
+Example:
+
+```dts
+&lt LOWER SPACE
+```
+
+### Configuration
+
+You can configure a different tapping term or tweak other properties noted in the [hold-tap](hold-tap.mdx#advanced-configuration) documentation page in your keymap:
+
+```dts
+&lt {
+    tapping-term-ms = <200>;
+};
+
+/ {
+    keymap {
+        ...
+    };
+};
+```
+
+:::info
+Functionally, the layer-tap is a [hold-tap](hold-tap.mdx) of the ["tap-preferred" flavor](hold-tap.mdx#flavors) and a [`tapping-term-ms`](hold-tap.mdx#tapping-term-ms) of 200 that takes in a [`momentary layer`](#momentary-layer) and a [keypress](key-press.md) as its "hold" and "tap" parameters, respectively.
+
+For users who want to send a different [keycode](../list-of-keycodes.mdx) depending on if the same key is held or tapped, see [Mod-Tap](mod-tap.md).
+
+Similarly, for users looking to create a keybind like the layer-tap that depending on how long the key is held, invokes behaviors like [sticky keys](sticky-key.md) or [key toggles](key-toggle.md), see [Hold-Tap](hold-tap.mdx).
+
+:::
+
+## To Layer
+
+The "to layer" behavior enables a layer and disables _all_ other layers _except_ the default layer.
+
+### Behavior Binding
+
+- Reference: `&to`
+- Parameter: The layer number to enable, e.g. `1`
+
+Example:
+
+```dts
+&to 3
+```
+
+## Toggle Layer
+
+The "toggle layer" behavior enables a layer if it is currently disabled, or disables it if enabled.
+
+### Behavior Binding
+
+- Reference: `&tog`
+- Parameter: The layer number to enable/disable, e.g. `1`
+
+Example:
+
+```dts
+&tog LOWER
+```
+
+## Conditional Layers
+
+The "conditional layers" feature enables a particular layer when all layers in a specified set are active.
+For more information, see [conditional layers](../conditional-layers.md).