doc: Add historical release notes for 0.16.1
doc: Add historical release notes for 0.16.1

Tree-SHA512: cca8188f954eeded58f705749b2ae51b08aadf4feddafaaafc57df2f84c10a3340a373c1602e9aa290c54b67cdcce53f61f4ca2db87bd98de5449afc53e25f86

DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin