Improve password and user entry

[farblos]

OraclePatchDownloader.java:

• Add methods readLine and readPassword that handle an absent console gracefully. Use the former to read the OTP.

• Read password from environment variable if possible.

• Read user and password from console if not specified on command line.

README.md:

• Sync option description from online help. Mark it as plain, non-shell verbatim text to avoid wrong syntax highlighting.

• Add note on password entry options. Expand example by environment variable reference.

[farblos]

After the 1st PR was well received (thanks) here comes the next one, this time a bit simpler.

I still have plans, though:

• Next PR would be dedicated to error handling and better maintainability - I'd like to have an option to get the pages dumped, so that it gets easier to spot problems when scraping fails.
• After that I'd like to implement some support for scraping the checksums from MOS and use them to verify the downloaded files, for example.

Hope this is OK with you to continue in that way - for me this was just the right project at the right time.

[ojehle]

After the 1st PR was well received (thanks) here comes the next one, this time a bit simpler.

I still have plans, though:

• Next PR would be dedicated to error handling and better maintainability - I'd like to have an option to get the pages dumped, so that it gets easier to spot problems when scraping fails.
• After that I'd like to implement some support for scraping the checksums from MOS and use them to verify the downloaded files, for example.

Hope this is OK with you to continue in that way - for me this was just the right project at the right time.

Thanks for improving the tool, will help all other users... i commented the password.match... not shure what the \A and \z will do, i prefer ^ and $ for start and end..