Enabled GitHub actions

[acidicMercury8]

Changes proposed in this pull request:

• Fixed build script
• Added basic NPM manifest
• Added GitHub Actions building workflow

Related issue:

• 11

Checklist:

• [x] My code is commented, has adequate variable/methods names, autoformatted or manually formatted
• [x] Code is not copy-pasted from leaked source codes of commercial projects, nor from projects protected with GPL-incompatible licenses
• [x] My pull request is complete and does not require any additional steps
• [x] (optional) I added my real name to the authors list and to the license sections of the modified source files, to improve protective power of the GPL license
• [x] I have checked automatic builds for this project and downloaded artifacts

Agreements

• [x] I agree to follow this project's Contributing Guidelines
• [x] I agree to follow this project's Code of Conduct