add default avatar image

Change-Id: I2a6b2266b292d9313d8059eedaf220d17fc4291d
Use another way to show the user detail info

Also re-use the popup form for both "add new user" and "modify user".

Change-Id: I7da447c5dac874da33cac1db5b7dded227135a79
refactor refreshpage refresh_userlist/userinfo

Change-Id: Ia03bc955f0bc323a5a90e76b226839e304788394