api: Add go files

I know this is a huge commit, but I can't be bothered to check
this in part by part.

api/commenter_session_new.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"net/http"
+	"time"
+)
+
+func commenterSessionNew() (string, error) {
+	session, err := randomHex(32)
+	if err != nil {
+		logger.Errorf("cannot create session hex: %v", err)
+		return "", errorInternal
+	}
+
+	statement := `
+		INSERT INTO
+		commenterSessions (session, creationDate)
+		VALUES            ($1,      $2          );
+	`
+	_, err = db.Exec(statement, session, time.Now().UTC())
+	if err != nil {
+		logger.Errorf("cannot insert new session: %v", err)
+		return "", errorInternal
+	}
+
+	return session, nil
+}
+
+func commenterSessionNewHandler(w http.ResponseWriter, r *http.Request) {
+	session, err := commenterSessionNew()
+	if err != nil {
+		writeBody(w, response{"success": false, "message": err.Error()})
+		return
+	}
+
+	writeBody(w, response{"success": true, "session": session})
+}