use vscode open command instead of open module for external links

[mohitsuman]

Fix #1249

[codecov]

Codecov Report

Merging #1254 into master will decrease coverage by 0.38%.
The diff coverage is 28%.

@@            Coverage Diff             @@
##           master    #1254      +/-   ##
==========================================
- Coverage    85.8%   85.42%   -0.39%     
==========================================
  Files          32       32              
  Lines        2255     2257       +2     
  Branches      401      401              
==========================================
- Hits         1935     1928       -7     
- Misses        320      329       +9

Impacted Files	Coverage Δ
src/odo.ts	79.4% <0%> (-0.04%)	⬇️
src/k8s/console.ts	13.55% <0%> (-3.75%)	⬇️
src/tools.ts	93.82% <0%> (-0.08%)	⬇️
src/openshift/cluster.ts	100% <100%> (ø)	⬆️
src/openshift/component.ts	93.51% <100%> (-0.02%)	⬇️
src/openshift/url.ts	96.07% <100%> (-2%)	⬇️

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