Fix many MarkDown issues in {NOTES*,README*,HACKING,LICENSE}.md files Reviewed-by: Tim Hudson <tjh@openssl.org> (Merged from https://github.com/openssl/openssl/pull/12109)
Rename NOTES*, README*, VERSION, HACKING, LICENSE to .md or .txt Reviewed-by: Tim Hudson <tjh@openssl.org> (Merged from https://github.com/openssl/openssl/pull/12109)
