Introduce settings profiles (#35339)

Settings Profiles

- [X] Allow profiles to be defined, where each profile can be any of
Zed's settings
    - [X] Autocompletion of all settings
    - [X] Errors on invalid keys
- [X] Action brings up modal that shows user-defined profiles
- [X] Alphabetize profiles
- [X] Ability to filter down via keyboard, and navigate via arrow up and
down
- [X] Auto select Disabled option by default (first in list, after
alphabetizing user-defined profiles)
- [X] Automatically select active profile on next picker summoning
- [X] Persist settings until toggled off
- [X] Show live preview as you select from the profile picker
- [X] Tweaking a setting, while in a profile, updates the profile live
- [X] Make sure actions that live update Zed, such as `cmd-0`, `cmd-+`,
and `cmd--`, work while in a profile
- [X] Add a test to track state

Release Notes:

- Added the ability to configure settings profiles, via the "profiles"
key. Example:

```json
{
  "profiles": {
    "Streaming": {
      "agent_font_size": 20,
      "buffer_font_size": 20,
      "theme": "One Light",
      "ui_font_size": 20
    }
  }
}
```

To set a profile, use `settings profile selector: toggle`

Cargo.lock

@@ -14755,6 +14755,25 @@ dependencies = [
  "zlog",
 ]
 
+[[package]]
+name = "settings_profile_selector"
+version = "0.1.0"
+dependencies = [
+ "editor",
+ "fuzzy",
+ "gpui",
+ "language",
+ "menu",
+ "picker",
+ "project",
+ "serde_json",
+ "settings",
+ "ui",
+ "workspace",
+ "workspace-hack",
+ "zed_actions",
+]
+
 [[package]]
 name = "settings_ui"
 version = "0.1.0"
@@ -20321,6 +20340,7 @@ dependencies = [
  "serde_json",
  "session",
  "settings",
+ "settings_profile_selector",
  "settings_ui",
  "shellexpand 2.1.2",
  "smol",