Allow roles for superroutes

[Crashillo]

Validation triggers ROLE_UNKNOWN error whenever a superroute contains any member tagged.

According to ​https://wiki.openstreetmap.org/wiki/Roles_for_recreational_route_relations, it's quite common that a hiking route (mainly) contains variations.

Can we append this to the defaultpresets.xml?

<roles>
  <role key="" text="route segment" requisite="required" type="relation" member_expression="type=route"/> <!-- fixme: at least 2 members are required -->
  
  <!-- new roles -->
  <role key="main" text="main route" requisite="optional" type="relation" member_expression="route=hiking"/>
  <role key="alternative" text="alternative route" requisite="optional" type="relation" member_expression="route=hiking"/>
  <role key="excursion" text="excursion route" requisite="optional" type="relation" member_expression="route=hiking"/>
  <role key="approach" text="approach route" requisite="optional" type="relation" member_expression="route=hiking"/>
  <role key="connection" text="connection route" requisite="optional" type="relation" member_expression="route=hiking"/>
</roles>