Make hst-core explicitly 'runtime' scope in hippo-cms-release pom

Currently, hst-core has already runtime scope in an end project because the hst-site-dependencies pom has:

    <dependency>
      <groupId>org.onehippo.cms7.hst.components</groupId>
      <artifactId>hst-core</artifactId>
      <version>${project.version}</version>
      <scope>runtime</scope>
    </dependency>

However, the above is quite brittle since the hippo-cms-release pom contains:

      <dependency>
        <groupId>org.onehippo.cms7.hst.components</groupId>
        <artifactId>hst-core</artifactId>
        <version>${hippo.hst.version}</version>
      </dependency>

Apparently, since the hippo-cms-release pom doesn't contain a scope, the scope turns out to be in an end project for hst-core to be runtime, but I suspect that if the hst-core gets pulled in by a different module that does not have <scope>runtime</scope> an end project might end up with hst-core as compile scope.

Hence, the hippo-cms-release pom should better specify explicitly

      <dependency>
        <groupId>org.onehippo.cms7.hst.components</groupId>
        <artifactId>hst-core</artifactId>
        <version>${hippo.hst.version}</version>
        <scope>runtime</scope>
      </dependency>

With an explicit scope, end projects seem to use the scope from the hippo-cms-release pom