Added configuration settings for SharePoint tab entity inside Teams

[roberAlb]

Configuration for SharePoint tab was empty. Basically, we have detected an issue trying to use de Website tab with a SharePoint site collection url, it works but all links inside that page loaded from the tab are not working. We have checked that they work if the tab is a SharePoint tab.

[luismanez]

Hitting this issue too. When we provision a Website Tab in a Team, pointing to a SP site using PnP Framework, all the links in the page that points to an "internal" url (tenant.sharepoint.com/...) are not working (curisously, links pointing to external sites, work fine).
Please @jansenbe could you have a look to this PR?

Here is the template part that provisions the Website teams tab pointing to a SP Site:

      <pnp:Channels>      
        <pnp:Channel DisplayName="General" Description="" IsFavoriteByDefault="true">
          <pnp:Tabs>
            <pnp:Tab DisplayName="Wiki" TeamsAppId="" Remove="true" />
            <pnp:Tab DisplayName="Home" TeamsAppId="com.microsoft.teamspace.tab.web">
              <pnp:Configuration EntityId="" ContentUrl="https://tenant.sharepoint.com/sites/marketing" RemoveUrl="" WebsiteUrl="https://tenant.sharepoint.com/sites/marketing" />
            </pnp:Tab>
          </pnp:Tabs>
        </pnp:Channel>
      </pnp:Channels>

Many thanks.

[jansenbe]

Good fix, thanks @roberAlb and @luismanez