Add example for AAD Service Principal connection

[RudraNirvan]

Fixes #749

[codecov]

Codecov Report

Merging #751 (06aa02b) into master (1598eaf) will decrease coverage by 0.16%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #751      +/-   ##
==========================================
- Coverage   71.32%   71.15%   -0.17%     
==========================================
  Files          24       24              
  Lines        5388     5388              
==========================================
- Hits         3843     3834       -9     
- Misses       1301     1307       +6     
- Partials      244      247       +3     

Impacted Files	Coverage Δ
tds.go	65.13% <0.00%> (-1.09%)	⬇️

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[RudraNirvan]

Force push to update author details in commit. No code change - can "Compare" to verify.