git_ui: Start unifying panel style with other panels (#24296)

- Adds the `panel` crate for defining UI shared between panels, like
common button and header designs, etc
- Starts to update the git ui to be more consistent with other panels

Release Notes:

- N/A

Cargo.toml

@@ -87,6 +87,7 @@ members = [
     "crates/open_ai",
     "crates/outline",
     "crates/outline_panel",
+    "crates/panel",
     "crates/paths",
     "crates/picker",
     "crates/prettier",
@@ -103,7 +104,6 @@ members = [
     "crates/remote_server",
     "crates/repl",
     "crates/reqwest_client",
-    "crates/reqwest_client",
     "crates/rich_text",
     "crates/rope",
     "crates/rpc",
@@ -243,8 +243,8 @@ fs = { path = "crates/fs" }
 fsevent = { path = "crates/fsevent" }
 fuzzy = { path = "crates/fuzzy" }
 git = { path = "crates/git" }
-git_ui = { path = "crates/git_ui" }
 git_hosting_providers = { path = "crates/git_hosting_providers" }
+git_ui = { path = "crates/git_ui" }
 go_to_line = { path = "crates/go_to_line" }
 google_ai = { path = "crates/google_ai" }
 gpui = { path = "crates/gpui", default-features = false, features = [
@@ -285,6 +285,7 @@ open_ai = { path = "crates/open_ai" }
 outline = { path = "crates/outline" }
 outline_panel = { path = "crates/outline_panel" }
 paths = { path = "crates/paths" }
+panel = { path = "crates/panel" }
 picker = { path = "crates/picker" }
 plugin = { path = "crates/plugin" }
 plugin_macros = { path = "crates/plugin_macros" }