Default Scoring Functions for Sphere, Rastrigin, Arm and Brax environments

[Lookatator]

• adding sphere, rastrigin, arm, and noisy_arm scoring functions
• adding possibility to create default scoring_function for brax environments.
• Changing type of EnvState to brax.envs.State
• Fix some quick typing inconsistencies throughout the code .
• update README to include the default functions and make it a usable readme
• create an examples directory to include script form of some examples

[codecov-commenter]

Codecov Report

Merging #73 (ed52ea6) into develop (ab4d4ca) will increase coverage by 1.03%.
The diff coverage is 95.53%.

@@             Coverage Diff             @@
##           develop      #73      +/-   ##
===========================================
+ Coverage    89.68%   90.72%   +1.03%     
===========================================
  Files           68       82      +14     
  Lines         3957     4572     +615     
===========================================
+ Hits          3549     4148     +599     
- Misses         408      424      +16     

Impacted Files	Coverage Δ
qdax/tasks/qd_suite/qd_suite_task.py	79.31% <79.31%> (ø)
qdax/tasks/brax_envs.py	88.33% <88.33%> (ø)
tests/default_tasks_test/qd_suite_test.py	92.68% <92.68%> (ø)
qdax/tasks/qd_suite/archimedean_spiral.py	93.54% <93.54%> (ø)
qdax/utils/plotting.py	36.36% <95.00%> (+2.90%)	⬆️
tests/default_tasks_test/arm_test.py	96.77% <96.77%> (ø)
tests/default_tasks_test/brax_task_test.py	97.14% <97.14%> (ø)
...s/default_tasks_test/hypervolume_functions_test.py	97.22% <97.22%> (ø)
...ests/default_tasks_test/standard_functions_test.py	97.22% <97.22%> (ø)
qdax/tasks/qd_suite/ssf.py	97.82% <97.82%> (ø)
... and 13 more

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

[felixchalumeau]

This file looks more like testing MAP-Elites rather than arm task. Maybe we could think about just a few simple tests that check the implementation works as expected.