Make code completion for hst tags work in webfiles

With ARCHE-456 we made code completion for beans work. But code completion for the hst tags is still failing. To make that work, you need to change the project setup of Intellij, that should be described on the .org.

But we also need some dependencies there (thanks to mmilicevic). Please add to the webfiles pom these dependencies:

<dependency>
<groupId>org.onehippo.cms7.hst.dependencies</groupId>
<artifactId>hst-client-dependencies</artifactId>
<type>pom</type>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
</dependency>
<dependency>
<groupId>org.apache.taglibs</groupId>
<artifactId>taglibs-standard-spec</artifactId>
</dependency>
<dependency>
<groupId>org.apache.taglibs</groupId>
<artifactId>taglibs-standard-impl</artifactId>
</dependency>

This is as addition to the already existing dependency on the site module. There would be no harm no add a comment here too that explains the purpose of these dependencies.