Redirect the deleted skin pages into metacatui

[taojing2002]

We are deleting the Metacat old skins, such as knb, obfs and et al. In order to avoid 404 when people access those deleted skins, Matthew proposed to use a servlet class to centralize the re-direction of the request. The web.xml file looks like:

<filter>
    <filter-name>ErrorFilter</filter-name>
    <filter-class>edu.ucsb.nceas.metacat.ErrorFilter</filter-class>
    <init-param>
        <param-name>excludePattern</param-name>
        <param-value>/style/skins/metacatui</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>ErrorFilter</filter-name>
    <url-pattern>/style/skins/*</url-pattern>
</filter-mapping>