Added AutomaticDefault module

[zsunberg]

This allows an algorithm writer to do, for example

using CommonRLInterface.AutomaticDefault: clone, valid_actions

Then clone will automatically try to use the clone provided by the environment, or fall back to deepcopy. Similarly valid_actions will use an environment's valid_actions or valid_action_mask or fall back to actions.

Still need to provide documentation. This will close #44 . I decided there was no need for an Optional module.

[codecov-io]

Codecov Report

Merging #47 (5ebd63a) into master (fe73ac2) will decrease coverage by 4.34%.
The diff coverage is 69.56%.

❗ Current head 5ebd63a differs from pull request most recent head c9cf82f. Consider uploading reports for the commit c9cf82f to get more accurate results

@@            Coverage Diff             @@
##           master      #47      +/-   ##
==========================================
- Coverage   74.46%   70.12%   -4.34%     
==========================================
  Files           3        6       +3     
  Lines          47       77      +30     
==========================================
+ Hits           35       54      +19     
- Misses         12       23      +11     

Impacted Files	Coverage Δ
src/CommonRLInterface.jl	100.00% <ø> (+17.64%)	⬆️
src/wrappers.jl	100.00% <ø> (ø)
src/automatic_default.jl	62.06% <62.06%> (ø)
src/optional.jl	81.25% <81.25%> (ø)
src/quick_wrapper.jl	65.38% <100.00%> (ø)

... and 1 file with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[zsunberg]

Ok, this is done! This is a fairly significant addition, so I will wait a few days for comments from any stakeholders (@the-one-and-only-jackson, @findmyway , @jeremiahpslewis, @HenriDeh ). If anyone wants to give a review, it is welcome!

[zsunberg]

Hearing no objections, I am going to merge this.