New bottom navbar

[Process-ing]

Closes #1267

It adds the new bottom navbar. To use it, the app needs to provide the navbar items, along with their icons and desired behaviors.

I also added a slight splash effect when clicked. If you think it should be removed, let me know.

Review checklist

• Terms and conditions reflect the current change
• Contains enough appropriate tests
• If aimed at production, writes a new summary in whatsnew/whatsnew-pt-PT
• Properly adds an entry in changelog.md with the change
• If PR includes UI updates/additions, its description has screenshots
• Behavior is as expected
• Clean, well-structured code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 12%. Comparing base (b6a2e08) to head (c721483).
Report is 7 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #1306   +/-   ##
=======================================
+ Coverage       12%     12%   +1%     
=======================================
  Files          266     266           
  Lines         7194    7198    +4     
=======================================
+ Hits           802     803    +1     
- Misses        6392    6395    +3     

[DGoiana]

Pretty cool work here! 💯