simplify authmgr, add goreleaser, remove old deps

Merge pull request #12 from rusq/authmgr

Authmgr refactor

Merge pull request #11 from rusq/csv

CSV file support and local file backup

job-task filenames mixed up

Merge pull request #2 from rusq/different-sources

Support different sources and .xls files

Merge pull request #1 from rusq/format-and-panic-fix

Target cells formatting and source file panic fix

import sort and comments