doc: Add historical release notes

Add all known release notes for versions since 0.3.12,
thanks to Matt Corallo for collecting them on the wiki.

doc/release-notes/release-notes-0.8.3.md

@@ -0,0 +1,18 @@
+Bitcoin-Qt version 0.8.3 is now available from:
+  http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.8.3/
+
+This is a maintenance release to fix a denial-of-service attack that
+can cause nodes to crash.
+
+Please report bugs using the issue tracker at github:
+  https://github.com/bitcoin/bitcoin/issues
+
+0.8.3 Release notes
+
+Truncate over-size messages to prevent a memory exhaustion attack.
+
+Fix a regression that causes excessive re-writing of the 'peers.dat' file.
+
+
+Thanks to Peter Todd for responsibly disclosing the vulnerability
+( CVE-2013-4627 ) and creating a fix.