Introduce blorg: MVP static site generator

hugo is nice - but it's huge. I've never built a static site generator before
and thought the world could use one more - it's not like there's already enough
choice out there!

No, but seriously. I love hugo and it has all the bells and whistles and you
should definitely use that and not this. I just like reinventing the wheel to
learn about stuff - and I like the 80/20 rule. This gives like 60% of what I
want already and is tiny fraction of hugo in terms of LOC (hugo without it's
bazillion dependencies is like 80k+ - this is like 500 and very likely won't
ever grow above let's say 5k).

Also org mode is awesome and why not use it as a configuration format as
well. Let's see where this goes. YOLO.

blorg/testdata/content/about.org

@@ -0,0 +1,4 @@
+#+TITLE: About
+#+TAG[]: static
+
+and some content

blorg/testdata/content/post.org

@@ -0,0 +1,2 @@
+#+TITLE: some post
+#+TAG[]: post