[FAB-3324][FAB-3439] - Getting Started Formatting

Add disclaimer at top
Add to troubleshooting
Fix reference to configtx.yaml
Code syntax updates
small grammatical fixes
update the environment variable for FABRIC_CFG_PATH
Fix URL for cURL command
Update readme for examples/dchackfest
[ci-skip]

Change-Id: I20e9207f41f20feed5b94573522c91379506c7f1
Signed-off-by: Nick Gaski <ngaski@us.ibm.com>