chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/languages/src/php/outline.scm

@@ -0,0 +1,29 @@
+(class_declaration
+    "class" @context
+    name: (name) @name
+    ) @item
+
+(function_definition
+    "function" @context
+    name: (_) @name
+    ) @item
+
+(method_declaration
+    "function" @context
+    name: (_) @name
+    ) @item
+
+(interface_declaration
+    "interface" @context
+    name: (_) @name
+    ) @item
+
+(enum_declaration
+    "enum" @context
+    name: (_) @name
+    ) @item
+
+(trait_declaration
+    "trait" @context
+    name: (_) @name
+    ) @item