Expose hashed passwords in slapos.cookbook:generate.password

• hashed password exposed directly in the recipe (release as slapos.cookbook 1.0.351)
• change most softwares to use hashed passwords instead of plain text
• simplify ERP5's password generation by using ${gen-password:passwd-ldap-salted-sha1} instead of implementing the password hashing ourselves in the template (with an approach that was not directly python3 compatible)
• other minor improvements to software/dufs