Chore : npm audit fix

[jungeun-cho]

Please check if the PR fulfills these requirements

• It's submitted to right branch according to our branching model
• It's right issue type on title
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes/features)
• Docs have been added/updated (for bug fixes/features)
• It does not introduce a breaking change or has description for the breaking change

Description

• refactor: remove unnecessary domo generator code
• chore: npm audit fix (resolve vulnerabilities)
  • webpack-dev-server (about http-proxy - https://www.npmjs.com/advisories/1486)
  • handlebars, karma-coverage, karma (about 'minimist' - https://www.npmjs.com/advisories/1179)

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Thank you for your contribution to TOAST UI product. 🎉 😘 ✨

[jungeun-cho]

ok to test

[jungeun-cho]

@dongsik-yoo please check this PR