Make new Rotation constructor and redefine anim_rotate[_around]

[leephillips]

to handle Integer and Irrational rotation angles.

PR Checklist

If you are contributing to Javis.jl, please make sure you are able to check off each item on this list:

• Did I update CHANGELOG.md with whatever changes/features I added with this PR?
• Did I make sure to only change the part of the file where I introduced a new change/feature?
• Did I cover all corner cases to be close to 100% test coverage (if applicable)?
• Did I properly add Javis dependencies to the Project.toml + set an upper bound of the dependency (if applicable)?
• Did I properly add test dependencies to the test directory (if applicable)?
• Did I check relevant tutorials that may be affected by changes in this PR?
• Did I clearly articulate why this PR was made the way it was and how it was made?

Link to relevant issue(s)
Closes #450

How did you address these issues with this PR? What methods did you use?

Added a constructor for Rotation that promotes arguments to have the same type;
changed type signatures of anim_rotate_around() and anim_rotate().

[TheCedarPrince]

Hey @leephillips !

Thank you for making this PR and working with @Wikunia on this!
I will let @Wikunia do a review of this more thoroughly as you have been working with him the most on this PR but one thing I notice is that the docstrings for these functions may need to be updated to reflect the new type signatures.

Also, we try to always recognize all contributors to Javis!
We will be sure to add your name to the list of our contributors in our README before we finish this PR.
You can also do that if you are willing but otherwise, we will take care of it for you.

Thanks @leephillips !

[leephillips]

”the docstrings for these functions may need to be updated to reflect the new type signatures.”

Quite right. I updated the docstrings in a new commit.

[Wikunia]

Thanks @leephillips
I've added a line to the changelog and changed your test cases a little bit.

[leephillips]

Looks good to me.

[Wikunia]

Test cases should pass after #455 is merged. 😉

[codecov-commenter]

Codecov Report

Merging #454 (ea51d39) into master (5731259) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #454   +/-   ##
=======================================
  Coverage   96.26%   96.26%           
=======================================
  Files          36       36           
  Lines        1633     1634    +1     
=======================================
+ Hits         1572     1573    +1     
  Misses         61       61           

Impacted Files	Coverage Δ
src/structs/Transitions.jl	94.44% <100.00%> (+0.32%)	⬆️

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