title: How to set PrimeNG theme?
body: <p>I am finding some problem trying to understand how to set the PrimeNG theme. If I go here:
  <a href="https://www.primefaces.org/primeng/showcase/#/table/crud" rel="nofollow noreferrer">https://www.primefaces.org/primeng/showcase/#/table/crud</a></p>
  <p>I can see that the theme set by default is the <strong>bootstrap4-light-blue</strong>.</p>
  <p>Ok, how can I set this theme in my project? I am using PrimeNG but I can't find themes into my project.</p>
  <p>Have I to install in some way? What am I missing?</p>
  <p><strong>EDIT-1:</strong> Into the folder of PrimeNg themes of my foler
  (/home/developer/Documents/Angular-WS/color_patch/node_modules/primeng/resources/themes) I only find these few themes? why? It seems to me that a lot of themes is missing. Isn't it?
  In particular the themes related to BootStrap seems to be not present</p>
  <p><a href="https://i.stack.imgur.com/3Y0Yi.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3Y0Yi.png" alt="enter image description here" /></a></p>