[FR]: use different workflows for test and release

[zsliu98]

Hi! I have just seen your post on the JUCE forum. And I think it might be a good time to make some changes to workflows.

This is related to #46. Pros and Cons of using different workflows are:

Pros:

• we have more flexibility to choose different plugin formats when building it locally / for the test / for the release
  • especially for AAX, since I have to download it back to sign on my local computer :(
• we don't need a fat binary for the test
• we don't need code-signing for the test

All of these Pros can shorten the test workflow execution time. And by removing the code-signing for the test, anyone can download & run the test without modification. They can then take care of code-signing when they are ready for the release.

Cons:

• if we change the building process (e.g., change the compiler), we have to copy-paste it for each workflow