Unify process header views

[mrcasals]

🎩 User Story

The mobile version of the process header changes depending on what page we are at. We should normalize this. For example:

http://decidim-design.herokuapp.com/info/ in mobile version:

http://decidim-design.herokuapp.com/phases/ in mobile version:

As you can see, the subtitle and the hashtag disappear, together with the cool steps visualization. Can we normalize this view? I'd go with using always the first one, as it is more complete. Note that the structure of files we are using at decidim makes it really hard to use different layouts for this section :(

📋 Related documentation

None

🎯 Acceptance criteria

Not specified

📌 Related issues

None.