Store LDAP password securely

[battis]

Fundamentally, because we actually need to store the password, it needs to be secured.

The SettingsPLugin mixin provides the ability to define settings preprocessors for loading and saving settings. But... empirically it appears that the preprocessors are not used when adjusting settings through a Jinja template (as one does). Additionally, the best option for securing the password in the settings would be to simply obscure it (e.g. base64 encoding). Which isn't real good.

A better option might be to store the password as an environment variable?