dc/hbj11: init with flasher

This brings in the flashing infrastructure for HBJ11 (bluepill&web).

Change-Id: I480855689f849c24712d58a0ccbce6e91c34f8bd
diff --git a/dc/hbj11/flasher/bluepill/.gitignore b/dc/hbj11/flasher/bluepill/.gitignore
new file mode 100644
index 0000000..eb5a316
--- /dev/null
+++ b/dc/hbj11/flasher/bluepill/.gitignore
@@ -0,0 +1 @@
+target