ci(markdown_lint): updated for mkdocs md files clarity.

added:
  two lines before headings
  one line after a heading
  max blank lines 2 (added due to heading rule)

This rules were added for clarity of markdown file editing.

MR !7

.markdownlint.json

@@ -5,5 +5,15 @@
   },
   "MD033": {
     "allowed_elements": [ "div", "s", "span", "u" ]
+  },
+  "blanks-around-headings":{
+    "lines_above": 2,
+    "lines_below": 1
+  },
+  "MD012": { 
+    "maximum": 2
+  }, 
+  "comment": {
+    "MD012": "MD012 max=2 added so that headings can have two lines above for clarity."
   }
 }