Main activity action should be stuck at the bottom

Following this prototype.

https://projects.invisionapp.com/share/UKAQRQQBP#/screens/223372193

Main actions on modules:

• Book Index: start-resume.
• File index: Open
• Folder: No action.
• IMSCP: start-resume (after MOBILE-3998)
• Page: No action.
• Url: Access the url.
• Assignment: Add, edit or submit submission. Too dificult: 4.1
• Chat: Enter the chat. Past sessions should stay in page as normal.
• Choice: Save / Remove my choice.
• Database: Add Entry (currently FAB Button). View Single entry? (4.1)
• Feedback: Preview, answer the questions, continue...
• Forum: Add post (currently FAB Button). (4.1)
• LTI: Launch the activity.
• Glossary: Add entry (currently FAB Button). (4.1)
• Lesson: Start / continue. On player: Review lesson, continue, submit?
• Quiz: Attempt. On player: Next, previous (navigation bar?), check review attempt...
• SCORM: Preview / Enter.
• Survey: Submit / Results
• Wiki: Add page (Currently FAB Button) (4.1). Edit page?
• Workshop: Add submission
• H5P: No action.
• BBB: Join Session