refactor: Refactor git hooks and templates organization

- Add a new file `git/hook.go` with a `embed.FS` variable and a `util.LoadTemplates` call in the `init` function.
- Rename `hook/templates/prepare-commit-msg` to `git/templates/prepare-commit-msg` with a 100% similarity index.
- Delete the file `hook/hook.go` and remove the `hook` package.

Author: appleboy

git/hook.go

@@ -0,0 +1,21 @@
+package git
+
+import (
+	"embed"
+	"log"
+
+	"github.com/appleboy/CodeGPT/util"
+)
+
+//go:embed templates/*
+var files embed.FS
+
+const (
+	CommitMessageTemplate = "prepare-commit-msg"
+)
+
+func init() {
+	if err := util.LoadTemplates(files); err != nil {
+		log.Fatal(err)
+	}
+}