#159236217 Enable getting exercises for a body part on mouse hover

[RrNn]

What does this PR do?

• This PR enables a user to view the exercises for a body part when he/she moves the mouse over that body part.

How should this be manually tested?

• Clone the application.
• Checkout the git branch ft-bodypart-hover-159236217
• Run the application python manage.py runserver
• Visit the muscle overview at http://127.0.0.1:8000/en/exercise/muscle/overview/
• Hover over the body parts and the exercises will change accordingly, just like they change on hovering over the exercise names.

Relevant Pivotal Tracker story.

• #159236217

[coveralls]

Pull Request Test Coverage Report for Build 524

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 92.887%

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Totals
Change from base Build 480:	0.3%
Covered Lines:	12628
Relevant Lines:	13595

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💛 - Coveralls