Remove unused npm dependencies

[xorye]

According to depcheck, vscode-quarkus has unused dependencies:

$ depcheck vscode-quarkus/
Unused dependencies
* @types/lodash
* @types/request
* @types/request-promise
* @types/unzipper
* fs-extra
* md5
* user-home
* xml2js
Unused devDependencies
* @types/fs-extra
* @types/md5
* @types/mocha
* @types/node
* @types/which
* @types/xml2js
* typescript-tslint-plugin
* webpack-cli