So first off... developing a 2d game engine is a massive project and most people will tell you to not do it. I'd definitely recommend starting with something simpler to learn.
I'll need a bit more information here. Specifically, why you're choosing C++ (since you're not that familiar with it, it would make more sense to use something you know well). And even more important, how experienced you are with programming and specifically game dev.
Something like bootstrap... the closest i can think of right now would be any ui-framework. Things like winforms (windows only and really old so probably don't use that). But that would make game dev pretty hard since you're using workarounds for pretty much everything. What I did when I started developing (with c++ and a 2d game engine as my first project... which was kinda stupid looking back, but still I don't regret it) was SFML. It provides pretty much everything you need from graphics, to sound, and even networking stuff. Thinking about it, it does actually provide some bootstrap-like things. Other popular options are stuff like SDL2 or OpenGL. i think sdl2 also includes stuff like physics so it's more gamedev specific but i like doing stuff the hard way haha.
If you want to make it web-based, why not use stuff like html5/css3 (with bootstrap lel)?
Edit: excuse my writing, i'm on mobile right now and kinda lazy. i'll fix it when i get home