Refrain from term 'Template Composer' in home screen

1) I suggest we change:

Please note that if the setup application encounters a preview HST configuration in your repository, it will be deleted automatically and you will lose any pending changes. Such a preview configuration is the result of changes made in the CMS Template Composer that you forgot to publish.

into

Make sure that you publish your changes in the CMS Channel Manager. Otherwise these changes, stored in the preview HST configuration, will be deleted automatically by this setup application and you will lose any pending changes.

2) also fix the second referral, see screenshot.