Replace Floating Action Buttons

[Bonsai8863]

Proposed changes

• Remove FAB on top-level entity pages; replace with distinct 'Create ' button at top
• On all entity page views change edit FAB to a distinct 'Edit' button up top
• On certain entity page views, add a 'Create Relationship' button next to the new edit button
• Remove popover in container header, as the edit and delete functionality will be covered by the edit button
• In the create relationship drawer, replace the FAB with two buttons at top: one for creating entities and one for creating observables

Checklist

• [x] I consider the submitted work as finished
• [x] I tested the code for its functionality
• [x] I wrote test cases for the relevant uses case
• [ ] I added/update the relevant documentation (either on github or on notion)
• [X] Where necessary I refactored code to improve the overall quality

Further comments

I've only implemented these changes on the Threat Actor Individual. Upon review and acceptance of this implementation, I will apply it everywhere else.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 67.69%. Comparing base (3ad8cfa) to head (27d728f).

:exclamation: Current head 27d728f differs from pull request most recent head 838d281. Consider uploading reports for the commit 838d281 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5269      +/-   ##
==========================================
- Coverage   67.81%   67.69%   -0.13%     
==========================================
  Files         538      532       -6     
  Lines       65478    65010     -468     
  Branches     5499     5445      -54     
==========================================
- Hits        44405    44009     -396     
+ Misses      21073    21001      -72     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[Bonsai8863]

This ticket is being decomposed into several other PRs.