Webclient: fix missing view config values (#208).

The default values of the view configuration "Viewable" and "Editable" settings are reflected in the GUI.
Actually their semantics is reversed and the settings renamed accordingly:
    "Viewable" -> "Hidden"
    "Editable" -> "Locked"

Pending for the "Rows" setting.

BREAKING CHANGES

2 Webclient URIs are changed and semantics is inverted:
    "dm4.webclient.viewable" -> "dm4.webclient.hidden"
    "dm4.webclient.editable" -> "dm4.webclient.locked"

In your plugins you must perform a search/replace accordingly and **invert the value**.
Especially your JSON migration files might be affected, e.g.
{{{
view_config_topics: [
    {
        type_uri: "dm4.webclient.view_config",
        composite: {
            dm4.webclient.viewable: false,      # -> dm4.webclient.hidden: true,
            dm4.webclient.editable: false       # -> dm4.webclient.locked: true
        }
    }
]
}}}

Defaults are hidden=false and locked=false.

See ticket 208.
Webclient: fix view config "Rows" default (#208).

This (client-side) error does not accur anymore:
{{{
    TextRendererError: field "xx" has no "rows" setting
}}}

If no "Rows" value is set (or if it is 0) then 1 is used as the default.

The "Rows" setting is renamed:
    "Rows" -> "Input Field Rows"

BREAKING CHANGES

1 view config URI is changed:
    "dm4.webclient.rows" -> "dm4.webclient.input_field_rows"

In your plugins you must perform a search/replace accordingly.
Especially your JSON migration files might be affected, e.g.
{{{
    view_config_topics: [
        {
            type_uri: "dm4.webclient.view_config",
            composite: {
                dm4.webclient.rows: 15      # -> dm4.webclient.input_field_rows: 15
            }
        }
    ]
}}}

NOTE 1: your custom renderers might need to be adapted. The "rows" property of the "page_model" object that is passed to the renderer functions is renamed to "input_field_rows".

NOTE 2: an **association definition** can no longer override a child type's view configuration setting with a **falsish** value (0, "", false). This is regarded as not needed anymore because the semantics of the former "Viewable" and "Editable" settings is inverted (see last commit).

See ticket 208.