Improve server open_browser feature #936

Job	Run time
build	2m 7s
Julia 1.6 - ubuntu-latest - x64	4m 10s
Julia 1.6 - macOS-latest - x64	4m 51s
Julia 1.6 - windows-latest - x64	10m 45s
Julia 1.8 - ubuntu-latest - x64	3m 44s
Julia 1.8 - macOS-latest - x64	7m 34s
Julia 1.8 - windows-latest - x64	6m 59s
Julia 1 - ubuntu-latest - x64	3m 37s
Julia 1 - macOS-latest - x64	6m 18s
Julia 1 - windows-latest - x64	5m 31s
Julia nightly - ubuntu-latest - x64	6m 5s
Julia nightly - macOS-latest - x64	9m 6s
Julia nightly - windows-latest - x64	7m 55s
	1h 18m 42s

Provide feedback