Use ~/.netrc for credentials, allow merging with local DNSMasq config…

…urations. (#9)

* Add use of .netrc file. Add ability to merge local configurations. Use temp file to avoid writing in current directory.

* add run script

* update run to use temp dir for venv

* Updated README.md and links to old script name, added ending comments

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Co-authored-by: Chris Davis <[email protected]>