Fix 11 Maintainability issues in shell\Convert-AcmeCERtoPFX.sh

[danielewood]

CodeFactor found multiple issues:

Use #!, not just #, for the shebang.

shell\Convert-AcmeCERtoPFX.sh:1

Use $(...) notation instead of legacy backticked ....

shell\Convert-AcmeCERtoPFX.sh:22 shell\Convert-AcmeCERtoPFX.sh:27 shell\Convert-AcmeCERtoPFX.sh:29 shell\Convert-AcmeCERtoPFX.sh:30 shell\Convert-AcmeCERtoPFX.sh:31 shell\Convert-AcmeCERtoPFX.sh:40 shell\Convert-AcmeCERtoPFX.sh:46 shell\Convert-AcmeCERtoPFX.sh:47 shell\Convert-AcmeCERtoPFX.sh:48

Useless echo? Instead of 'echo $(cmd)', just use 'cmd'.

shell\Convert-AcmeCERtoPFX.sh:47