Gh pages deploy fix (#5669)

* fix(app):redirect after 404

* fix(app):docs building script

* fix(app):add gulpfile for docs

* fix(app): directory splitting

* fix(app): build docs script

* fix(app): build docs script

* fix(app): build docs script

* fix(app): relative path for scss

* fix(app): relative path for scss

* fix(app): relative path for scss

* fix(app):fix footer icons

* fix(app):fix footer icons

* fix(app):fix footer icons

* fix(app):config

* fix(app):remove small-social

* fix(docs): footer icons style

* fix(docs): material page index file

* fix(docs): descriptions and keyword

* fix(docs): og description

* fix(docs): og description and title

* fix(docs): dem,o branch url

* fix(docs): dynamic title for docs page

* fix(docs): remove unused script

* fix(docs): static title

Co-authored-by: Evgeny Lupanov <e.lupanov@akveo.com>

docs/app/@theme/styles/_helvetica-neue.scss

@@ -4,7 +4,7 @@
  * Licensed under the MIT License. See License.txt in the project root for license information.
  */
 
-$helvetica-neue-font-path: 'assets/fonts/helvetica-neue' !default;
+$helvetica-neue-font-path: '/ngx-admin/assets/fonts/helvetica-neue' !default;
 
 @font-face {
   font-family: 'Helvetica Neue Bold';

docs/app/@theme/styles/_small-social.scss

@@ -1,36 +0,0 @@
-$small-social-font-path: '/assets/fonts/small-social' !default;
-@font-face {
-  font-family: 'small-social';
-  font-display: auto;
-  src:  url('#{$small-social-font-path}/small-social.eot?skntni');
-  src:  url('#{$small-social-font-path}/small-social.eot?skntni#iefix') format('embedded-opentype'),
-  url('#{$small-social-font-path}/small-social.ttf?skntni') format('truetype'),
-  url('#{$small-social-font-path}/small-social.woff?skntni') format('woff'),
-  url('#{$small-social-font-path}/small-social.svg?skntni#small-social') format('svg');
-  font-weight: normal;
-  font-style: normal;
-}
-
-[class^='small-social-'], [class*=' small-social-'] {
-  font-family: 'small-social' !important;
-  speak: none;
-  font-style: normal;
-  font-weight: normal;
-  font-variant: normal;
-  text-transform: none;
-  line-height: 1;
-
-  /* Better Font Rendering =========== */
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-}
-
-.small-social-facebook::before {
-  content: '\e900';
-}
-.small-social-github::before {
-  content: '\e901';
-}
-.small-social-twitter::before {
-  content: '\e902';
-}

docs/app/@theme/styles/styles.scss

@@ -4,7 +4,6 @@
  * Licensed under the MIT License. See License.txt in the project root for license information.
  */
 
-@import 'small-social';
 @import 'helvetica-neue';
 @import 'themes';