'Buffer' defined for the contract function executed in browser environment

• adds Buffer, atob, btoa to the browser version of contract function so it can be defined inside the contract when state is evaluated in the browser
• removes polyfills from the web bundle (introduced in v1.2.29)
• upgrades arweave-js version to 1.11.8 (which fixes issues with tx signature verification)
• changes smartweave-nlp-extension plugin's name to smartweave-nlp-extension and smartweave-ethers-extension to smartweave-extension-ethers

What's Changed

• feat: buffer fight by @asiaziola in #279

Full Changelog: v1.2.29...v1.2.30