Custom ImGui JS binding to support latest version

[poirierlouis]

Current ImGui embedded is based on imgui-js which doesn't support the latest version of ImGui.
Library is not usable as a package in a Typescript/Angular environment, no install and code.
Some issues, like copy/paste shortcuts were fixed directly in the minified .umd.js file.
It does not provide an API to manage where to store ImGui states (e.g. restore window positions).

Either author is still maintaining and could provide upgrades, is open for changes, or an entire standalone project could be written with these requirements in mind.
It could then be easily integrated in FIG.