show Salesforce Login as full size and hide installation steps if no
connected org
- Add Cancelled status for Installation Step
- Set pending sibling steps to Cancelled when a step fails
- Fix icons on installation_overview
- Delete org_packages and metadata from session after starting an
  installation
- Redirect to post_login if org_packages or metadata are not set in the
  session
- Add tinymce fields for content
- Include contextual content in templates (intro, success, failure)
- Show log of failed steps on installation_overview
- Fix typo in requirements.txt
- Change package_version_overview to use get_content_intro
Add tinymce configuration to get more buttons