A new Site-to-Site setup guide (#480)

* wip: new Site-to-Site guide

* wip: Site-to-Site guide with access controlls

* wip: Site-to-Site without masquerading

* feat: Site-to-Site setup guide

* amended wording/grammar, moved to new 'use cases' directory

* fix: missing some bold terms

* fix: revert headings changes

* Added styling for h4 headers, removed site-to-site doc from how-to directory

* moved images to correct directory

---------

Co-authored-by: Ashley Mensah <ashley@netbird.io>

typography.js

@@ -201,6 +201,14 @@ module.exports = ({ theme }) => ({
         marginTop: theme('spacing.10'),
         marginBottom: theme('spacing.2'),
       },
+      h4: {
+        color: 'var(--tw-prose-headings)',
+        fontSize: theme('fontSize.sm')[0],
+        ...theme('fontSize.sm')[1],
+        fontWeight: '600',
+        marginTop: theme('spacing.8'),
+        marginBottom: theme('spacing.2'),
+      },
 
       // Media
       'img, video, figure': {