Blog: migrate metadata for 2014–2019

Also, adjust some formatting for Redocly (admonitions, indented code
blocks, authorship lines)

blog/2017/invariant-checking.md

@@ -1,7 +1,16 @@
+---
+category: 2017
+labels:
+    - Features
+date: 2017-07-19
+theme:
+    markdown:
+        editPage:
+            hide: true
+author: Nik Bougalis
+---
 # Protecting the Ledger: Invariant Checking
 
-_By Nik Bougalis, Engineering Manager_
-
 At Ripple, we have been developing next-generation financial infrastructure with an eye towards making value move as fast and as efficiently as information does today.
 
 But we are also keenly aware of the need for value to also move securely and reliably, so we place heavy emphasis on writing solid, secure and robust code. Our singular focus on code quality is the reason that the Ripple network experienced no service outages through 2016 or, so far, in 2017.