feat: Add Sync policy (#70)

* feat: Add Sync policy

* Apply suggestion from @bsmth

* Apply suggestion from @1rneh

Co-authored-by: Janika <92304290+1rneh@users.noreply.github.com>

* feat: Sync policy revision following reviewer comments

---------

Co-authored-by: Janika <92304290+1rneh@users.noreply.github.com>

Author: bsmth

src/content/docs/reference/policies/Sync.mdx

@@ -0,0 +1,117 @@
+---
+title: "Sync"
+description: "Enable or disable sync and define which data to include."
+category: "Local data storage"
+---
+
+Controls whether [sync](https://www.firefox.com/en-US/features/sync/) should be enabled and which features should be enabled for syncing.
+
+> [!NOTE]
+> Currently, this is only implemented in Firefox Enterprise.
+
+**Compatibility:** Firefox Enterprise 150.0.0\
+**CCK2 Equivalent:** N/A\
+**Preferences Affected:** N/A
+
+## Values
+
+- `Addons`: A Boolean. Controls whether syncing addons should be enabled.
+- `Addresses`: A Boolean. Controls whether syncing addresses should be enabled.
+- `Bookmarks`: A Boolean. Controls whether syncing bookmarks should be enabled.
+- `Enabled`: A Boolean. Controls whether sync itself should be enabled.
+- `History`: A Boolean. Controls whether syncing history should be enabled.
+- `Locked`: A Boolean. Controls whether to lock the customized sync settings.
+- `OpenTabs`: A Boolean. Controls whether syncing open tabs should be enabled.
+- `Passwords`: A Boolean. Controls whether syncing passwords should be enabled.
+- `PaymentMethods`: A Boolean. Controls whether syncing payment methods should be enabled.
+- `Settings`: A Boolean. Controls whether syncing settings should be enabled.
+
+## Windows (GPO)
+
+```
+Software\Policies\Mozilla\Firefox\Sync\Addons = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\Addresses = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\Bookmarks = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\Enabled = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\History = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\Locked = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\OpenTabs = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\Passwords = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\PaymentMethods = 0x1 | 0x0
+Software\Policies\Mozilla\Firefox\Sync\Settings = 0x1 | 0x0
+```
+
+## Windows (Intune)
+
+OMA-URI:
+
+```url
+./Device/Vendor/MSFT/Policy/Config/Firefox~Policy~firefox/Sync
+```
+
+Value (string):
+
+```xml
+<enabled/> or <disabled/>
+<data id="Addons" value="true | false"/>
+<data id="Addresses" value="true | false"/>
+<data id="Bookmarks" value="true | false"/>
+<data id="Enabled" value="true | false"/>
+<data id="History" value="true | false"/>
+<data id="Locked" value="true | false"/>
+<data id="OpenTabs" value="true | false"/>
+<data id="Passwords" value="true | false"/>
+<data id="PaymentMethods" value="true | false"/>
+<data id="Settings" value="true | false"/>
+```
+
+## macOS
+
+```xml
+<dict>
+  <key>Sync</key>
+  <dict>
+    <key>Addons</key>
+    <true/> | <false/>
+    <key>Addresses</key>
+    <true/> | <false/>
+    <key>Bookmarks</key>
+    <true/> | <false/>
+    <key>Enabled</key>
+    <true/> | <false/>
+    <key>History</key>
+    <true/> | <false/>
+    <key>Locked</key>
+    <true/> | <false/>
+    <key>OpenTabs</key>
+    <true/> | <false/>
+    <key>Passwords</key>
+    <true/> | <false/>
+    <key>PaymentMethods</key>
+    <true/> | <false/>
+    <key>Settings</key>
+    <true/> | <false/>
+  </dict>
+</dict>
+```
+
+## policies.json
+
+```json
+{
+  "policies": {
+    "Sync": {
+      "Addons": true | false,
+      "Addresses": true | false,
+      "Bookmarks": true | false,
+      "Enabled": true | false,
+      "History": true | false,
+      "Locked": true | false,
+      "OpenTabs": true | false,
+      "Passwords": true | false,
+      "PaymentMethods": true | false,
+      "Settings": true | false
+    }
+  }
+}
+```