Change password generator for new users.

[FlusherDock1]

md5(microtime(true)); - creates way to long password string, that is not really friendly to new customers. Example: 280a9a19a0cadaa2ce4092251e065113

str_random(8) - Generates 8 alphanumeric string, that is more friendly and easier to read or remember.
Example: Ms6epOqT

[kharanenka]

Thanks for your contribution