entrypoint/: let Icinga Web render its config files, not a Go lib

[Al2Klimov]

It knows best what they have to look like to be interpreted correctly. Especially the proper quoting of special characters is important.

closes #119

Before

[Administrators]
permissions = *
users       = icingaadmin
groups      = Administrators

After

[Administrators]
groups = "Administrators"
permissions = "*"
users = "icingaadmin"