refactor: move bootstrap under assets/_scss

we are tracking the node_modules folder and not using npm in a typical manner
this commit removes the node_modules folder and moves the (tracked) bootstrap
dependency into our _scss folder, which then allows us to remove the npm
package.json and lock file
we are using jquery and popper.js but we weren't referencing the files in
node_modules but ones in CDNs

Author: phette23