feat(v2): meta description (#1447)

* feat(v2): meta description

* add description for blog as well

* fix non-descriptive text link

* remove font awesome

* switch front-matter -> gray-matter

packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/website/docs/foo/bar.md

@@ -1,6 +1,7 @@
 ---
 id: bar
 title: Bar
+description: This is custom description
 ---
 
 # Remarkable

packages/docusaurus-plugin-content-docs/src/__tests__/index.test.js

@@ -39,6 +39,7 @@ describe('loadDocs', () => {
       sidebar: 'docs',
       source: path.join(docsDir, 'hello.md'),
       title: 'Hello, World !',
+      description: `Hi, Endilie here :)`,
     });
     expect(docsMetadata['foo/bar']).toEqual({
       category: 'Test',
@@ -49,6 +50,7 @@ describe('loadDocs', () => {
       sidebar: 'docs',
       source: path.join(docsDir, 'foo', 'bar.md'),
       title: 'Bar',
+      description: 'This is custom description',
     });
   });
 });

packages/docusaurus-plugin-content-docs/src/__tests__/metadata.test.js

@@ -40,12 +40,14 @@ describe('processMetadata', () => {
       permalink: '/docs/foo/bar',
       source: path.join(docsDir, sourceA),
       title: 'Bar',
+      description: 'This is custom description',
     });
     expect(dataB).toEqual({
       id: 'hello',
       permalink: '/docs/hello',
       source: path.join(docsDir, sourceB),
       title: 'Hello, World !',
+      description: `Hi, Endilie here :)`,
     });
   });
 
@@ -57,6 +59,7 @@ describe('processMetadata', () => {
       permalink: '/docs/endiliey/permalink',
       source: path.join(docsDir, source),
       title: 'Permalink',
+      description: 'This has a different permalink',
     });
   });
 });