Add and use Tailwind CSS typography plugin

Replace custom markup styles with Tailwind CSS's typography/prose plugin
(https://github.com/tailwindlabs/tailwindcss-typography).

web/themes/custom/opdavies/assets/css/components/markup.pcss

@@ -1,115 +0,0 @@
-.markup {
-  a {
-    @apply underline;
-
-    &:hover {
-      @apply no-underline
-    }
-
-    &:focus {
-      @apply p-px -m-px bg-blue-700 text-white outline-none
-    }
-  }
-
-  p {
-    @apply leading-relaxed;
-
-    + p {
-      @apply mt-4
-    }
-  }
-
-  ol {
-    @apply list-decimal
-  }
-
-  ul {
-    @apply list-disc;
-  }
-
-  ol,
-  ul {
-    @apply pl-5;
-
-    + * {
-      @apply mt-4
-    }
-
-    li + li {
-      @apply mt-2
-    }
-  }
-
-  p {
-    + blockquote,
-    + ol,
-    + ul,
-    + div[v-pre] {
-      @apply mt-4
-    }
-  }
-
-  blockquote + * {
-    @apply mt-4
-  }
-
-  code {
-    @apply -my-px px-1 py-px border border-gray-400 text-sm bg-gray-200
-  }
-
-  pre {
-    @apply border-l-3 border-gray-400 text-sm bg-gray-200;
-
-    code {
-      @apply p-6 block border-none leading-loose text-sm overflow-x-scroll
-    }
-  }
-
-  * + pre,
-  * + div[v-pre] {
-    @apply my-4
-  }
-
-  img,
-  figure {
-    @apply my-8
-  }
-
-  figure {
-    img {
-      @apply m-0
-    }
-
-    figcaption {
-      @apply mt-3
-    }
-  }
-
-  h2 {
-    @apply leading-tight
-  }
-
-  * + h2 {
-    @apply mt-6
-  }
-
-  h2 + * {
-    @apply mt-3
-  }
-
-  h3 {
-    @apply text-xl font-bold leading-tight
-  }
-
-  * + h3 {
-    @apply mt-6
-  }
-
-  h3 + * {
-    @apply mt-2
-  }
-
-  h2 + h3 {
-    @apply mt-4
-  }
-}

web/themes/custom/opdavies/assets/css/custom-components.pcss

@@ -1,7 +1,6 @@
 @import './components/button.pcss';
 @import './components/container.pcss';
 @import './components/lead.pcss';
-@import './components/markup.pcss';
 @import './components/note.pcss';
 @import './components/recommendation.pcss';
 @import './components/table.pcss';