feat(auth): added multi-language support to logIn method

[YuryShkoda]

Issue

Closes #835

Intent

• Add multi-language support to logIn method of the AuthManager.

Implementation

• Added getExpectedLogInSuccessHeader function to src/auth/loginHeader.ts.
• Added isLogInSuccessHeaderPresent function to src/auth/loginHeader.ts.
• Added getUserLanguage utility.

Checks

No PR (that involves a non-trivial code change) should be merged, unless all items below are confirmed! If an urgent fix is needed - use a tar file.

• Unit tests coverage has been increased and a new threshold is set.
• All sasjs-cli unit tests are passing (npm test).
• (CI Runs this) All sasjs-tests are passing. If you want to run it manually (instructions available here).
• Data Controller builds and is functional on both SAS 9 and Viya

[gh4nh]

@allanbowe I've downloaded and implemented the index.min.js and successfully tested with a German and English browser. Thank you for your speedy fix.