refactor!: export types from barrel file

[metonym]

Currently, this library uses sveld to generate TypeScript definitions.

This is a breaking change that instead re-exports and re-uses a base CarbonPictogram class from the barrel file. Reasons are as follows:

• Smaller package
• Much faster to build the library
• Consistent with the approach by carbon-icons-svelte

There should technically be no functional changes, but a major version bump is likely warranted.