Add --group and --only-group to uv sync and includes all groups in uv lock (#8110)

Part of #8090

Adds the ability to include a group (`--group`) in the sync or _only_
sync a group (`--only-group`). Includes all groups in the resolution,
which will have the same limitations as extras as described in #6981.

There's a great deal of refactoring of the "development" concept into
"groups" behind the scenes that I am continuing to defer here to
minimize the diff.

Additionally, this does not yet resolve interactions with the existing
`dev` group — we'll tackle that separately as well. I probably won't
merge the stack until that design is resolved. The current proposal is
that we'll just "combine' the `dev-dependencies` contents into the `dev`
group.

crates/uv-cli/src/lib.rs

@@ -2788,6 +2788,20 @@ pub struct SyncArgs {
     #[arg(long, conflicts_with("no_dev"))]
     pub only_dev: bool,
 
+    /// Include dependencies from the specified local dependency group.
+    ///
+    /// May be provided multiple times.
+    #[arg(long, conflicts_with("only_group"))]
+    pub group: Vec<GroupName>,
+
+    /// Only include dependencies from the specified local dependency group.
+    ///
+    /// May be provided multiple times.
+    ///
+    /// The project itself will also be omitted.
+    #[arg(long, conflicts_with("group"))]
+    pub only_group: Vec<GroupName>,
+
     /// Install any editable dependencies, including the project and any workspace members, as
     /// non-editable.
     #[arg(long)]