Add inTextImg shortcode

Allows adding in-line-text images

usage in page.md =>
This image is inlined {{< inTextImg.html url="image.png" >}} here.

optional args:
- height
- alt

assets/css/common/post-single.css

@@ -393,4 +393,9 @@ h6:hover .anchor {
 
 h1>a>svg {
     display: inline;
+}
+
+img.in-text {
+    display: inline;
+    margin: auto;
 }