v4: Social meta tags (#20825)

* descriptions for getting started pages

* descriptions for layout

* add content page descriptions

* more descriptions, updates to some existing ones

* correct site url

* add social stuff to config for twitter cards

* add twitter meta tags; use large image for homepage and regular card for all others

* add the assets

* more site config

* more social shiz to partial, remove existing meta for the partial, remove page title from homepage for simpler if statements

docs/about/brand.md

@@ -1,6 +1,7 @@
 ---
 layout: docs
 title: Brand guidelines
+description: Documentation and examples for Bootstrap's logo and brand usage guidelines.
 group: about
 ---
 

docs/about/history.md

@@ -1,6 +1,7 @@
 ---
 layout: docs
 title: History
+description: A brief overview of the history of Bootstrap.
 group: about
 redirect_from: "/about/"
 ---

docs/about/license.md

@@ -1,6 +1,7 @@
 ---
 layout: docs
 title: License FAQs
+description: Commonly asked questions about Bootstrap's open source license.
 group: about
 ---
 

docs/about/team.md

@@ -1,6 +1,7 @@
 ---
 layout: docs
 title: Team
+description: An overview of the founding team and core contributors to Bootstrap.
 group: about
 ---
 

docs/about/translations.md

@@ -1,6 +1,7 @@
 ---
 layout: docs
 title: Translations
+description: Links to community-translated Bootstrap documentation sites.
 group: about
 ---