docs: remove duplicated (and outdated) site docs

At the moment, we don't have a good guideline for package-specific
configuration, but it seems like a good idea not to split configuration
into too many tiny pages, especially for packages that aren't commonly
selected explicitly.

Some uncommon configuration is dropped from the example site.conf to remove
clutter.

docs/index.rst

@@ -55,9 +55,7 @@ Several Freifunk communities in Germany use Gluon as the foundation of their Fre
    :maxdepth: 1
 
    package/gluon-client-bridge
-   package/gluon-config-mode-contact-info
    package/gluon-config-mode-domain-select
-   package/gluon-config-mode-geo-location
    package/gluon-ebtables-filter-multicast
    package/gluon-ebtables-filter-ra-dhcp
    package/gluon-ebtables-source-filter

docs/package/gluon-config-mode-contact-info.rst

-gluon-config-mode-contact-info
-==============================
-
-This package allows the user to provide contact information within config mode
-to be distributed in the mesh. You can define whether the owner contact field is
-obligatory or not in your ``site.conf``.
-
-site.conf
----------
-
-config_mode.owner.obligatory \: optional
-    - ``true`` the contact info field must be supplied and may not be left empty.
-    - ``false`` the contact info field may be left empty.
-    - defaults to ``false``
-
-Example::
-
-  config_mode = {
-    owner = {
-      obligatory = true
-    }
-  }

docs/package/gluon-config-mode-geo-location.rst

-gluon-config-mode-geo-location
-==============================
-
-This package enables the user to set latitude, longitude and altitude of their
-node within config mode. As the usage of the altitude is not well defined the
-corresponding field can be disabled in your ``site.conf``.
-
-site.conf
----------
-
-config_mode.geo_location.show_altitude : optional
-    - ``true`` enables the altitude field
-    - ``false`` disables the altitude field if altitude has not yet been set
-    - defaults to ``true``
-
-Example::
-
-  config_mode = {
-    geo_location = {
-      show_altitude = true,
-    }
-  }

docs/site-example/site.conf

@@ -186,37 +186,4 @@
       },
     },
   },
-
-  -- Node roles
-  -- roles = {
-    -- default = 'node',
-    -- list = {
-      -- 'node',
-      -- 'test',
-      -- 'backbone',
-      -- 'service',
-    -- },
-  -- },
-
-  -- Skip setup mode (config mode) on first boot
-  -- setup_mode = {
-    -- skip = true,
-  -- },
-
-  -- config_mode = {
-    -- Show/hide the altitude field
-    -- geo_location = {
-      -- show_altitude = false,
-    -- },
-    -- define if the contact field is obligatory (optional)
-    -- owner = {
-      -- obligatory = true,
-    -- },
-    -- Show/hide the password login
-    -- remote_login = {
-      -- show_password_form = true,
-      -- min_password_length = 12,
-    -- },
-  -- },
-
 }