#8761: update internal/external naming from `brick` to `package` in the Workshop

[twschiller]

What does this PR do?

• Closes #8761
• Updates internal/external naming from brick to package. (Because not everything is a "brick" anymore)

Remaining Work

• [x] Fix broken playwright tests - having trouble with authentication fixture when running locally

Discussion

• package is a reserved keyword in JS. So uses a modifier, e.g., editablePackage, packageMetadata, etc. where appropriate

Demo

Future Work

• Rename BrickIcon to PackageIcon because it's also used for mods/integrations
• Rename Metadata to something more informative of how it's actually used, e.g., PackageBase: https://github.com/pixiebrix/pixiebrix-extension/blob/dd6e58e650d16acee0e8318cb2d4546b5bccb50a/src/types/registryTypes.ts#L63-L63

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