Unfortunately CSS is always global, so there's no easy way of doing this.
One way however, is to recompile Bootstrap and wrap it in a wrapper class.
Then, in your code, setup the wrapper class on a wrapper component and only classes that will be inside that wrapper component will be affected by Bootstrap classes.
Steps to do it :
(you'll need npm to do it)
- download bootstrap sources here
 
- unzip it, go in ./scss/bootstrap.scss
 
- add a wrapper css class on all 
@import like so : 
.local-bootstrap {
  @import "function";
  @import "variables";
  /* ... */
  @import "print";
}
- go back to the root of the unzipped directory
 
- run 
npm install and npm run css-compile 
- your local bootstrap is in ./dist/css/bootstrap.css, that's what you can add to your project
 
Then in your code :
 <div class="local-bootstrap"> /* wrapper component */
   /* inside, the code is affected by your local bootstrap */
   <div class="alert alert-primary" role="alert"/>
 </div>
 /* outside it is not */
 <div>
 </div>
That said, it's pretty sure that the javascript part of bootstrap won't fully work because it relies on classes, this is a bit hacky, anyway.