Add keyword-based library search and refactor copilot package structure#681

xlight05 merged 1 commit intoballerina-platform:copilot-library-unifyballerina-platform/ballerina-language-server:copilot-library-unifyfrom

VellummyilumVinoth:external-libraries-searchVellummyilumVinoth/ballerina-language-server:external-libraries-searchCopy head branch name to clipboard