cmake: Set top-level target output locations

This change:
1. Collects build artifacts in dedicated locations.
2. Allows running bitcoin-chainstate.exe with bitcoinkernel.dll directly
from the build tree on Windows.

contrib/devtools/gen-manpages.py

@@ -9,12 +9,12 @@ import tempfile
 import argparse
 
 BINARIES = [
-'src/bitcoind',
-'src/bitcoin-cli',
-'src/bitcoin-tx',
-'src/bitcoin-wallet',
-'src/bitcoin-util',
-'src/qt/bitcoin-qt',
+'bin/bitcoind',
+'bin/bitcoin-cli',
+'bin/bitcoin-tx',
+'bin/bitcoin-wallet',
+'bin/bitcoin-util',
+'bin/bitcoin-qt',
 ]
 
 parser = argparse.ArgumentParser(