Allow metric admins table schema view access

The metrics groups wants to be able to view the schema behind ServiceNow to further their understanding. Problem is that the "Tables and Columns" view is currently only available to admins. Here are the changes that would need to be made so they can view that.

System Definition Application
1. Add role metric_admin
Tables and Columns Module
1. Add role metric_admin
System Security > Access Controls
1. Add role metric_admin
Alter

<if test="$[gs.hasRole('admin')]">
    <tr valign="top">
        <td colspan="3">
            <if test="$[pm.isRegistered('com.glideapp.schema_map2')]">
                <inline template="schema2_includes.xml"/>
            </if>
            <if test="$[!pm.isRegistered('com.glideapp.schema_map2')]">
                <if test="$[pm.isRegistered('com.glideapp.schema_map')]">
                    <inline template="schema_includes.xml"/>
                </if>
            </if>
            <inline template="delete_rows_includes.xml"/>
            <if test="${gs.getProperty('glide.table.allow_new_extension', 'false') == 'true'}">
                <button id="allowextension_button" onclick="allowExtension();" title="${gs.getMessage('Allow this table to be extended in the Table creator below')}" style="display:none;">${gs.getMessage('Allow extension')}</button>
            </if>
        </td>
    </tr>
</if>