Code cleanup

[ZoeyR]

This PR addresses multiple issues to help clean up the code

• switch to cargo workspaces
• make sure tests pass on all platforms
• use the correct repo links
• switch to azure pipelines

The azure pipelines switch isn't complete yet because this repo needs to be set up to connect to azure. I'm not an admin/owner so I can't configure that myself.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@6289ff1). Click here to learn what that means.
The diff coverage is 28.57%.

@@            Coverage Diff            @@
##             master       #1   +/-   ##
=========================================
  Coverage          ?   85.95%           
=========================================
  Files             ?       17           
  Lines             ?      349           
  Branches          ?        0           
=========================================
  Hits              ?      300           
  Misses            ?       49           
  Partials          ?        0

Impacted Files	Coverage Δ
dotenv/src/iter.rs	95.83% <ø> (ø)
dotenv/src/find.rs	92.59% <ø> (ø)
dotenv/src/errors.rs	0% <ø> (ø)
dotenv/src/lib.rs	100% <ø> (ø)
dotenv/src/parse.rs	98.4% <ø> (ø)
dotenv_codegen_impl/src/lib.rs	0% <0%> (ø)
dotenv/tests/test-default-location.rs	87.5% <100%> (ø)
dotenv/tests/test-from-filename-iter.rs	90% <100%> (ø)
dotenv/tests/test-from-path-iter.rs	91.66% <100%> (ø)
dotenv/tests/test-from-path.rs	90% <100%> (ø)
... and 6 more

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[projektir]

Looks good overall. Please squash the commits. :)