Add beekeeper signatures provider

examples/ts/signature-extension/package.json

examples/ts/signature-extension/test/index.html

ts/packages/signers-beekeeper/README.md

ts/packages/signers-beekeeper/package.json

ts/packages/signers-beekeeper/src/index.ts

ts/packages/signers-beekeeper/tsconfig.json

ts/pnpm-lock.yaml