Implement a "slim" WASM packaging for `nucypher-core`

[piotr-roslaniec]

• Implement an alternative "slim" export in the nucypher-core package for WASM-aware bundlers
• Provides nucypher-core users with a lightweight (~33% smaller) alternative for "fat" export which contains base64-encoded inlined WASM
• Consider merging the nucypher-core-wasm and nucypher-core-wasm-bundler directories on the back of this change
• Refers to Inline WASM in @nucypher/nucypher-core NPM package #83