Rewrite VBscripts in installers in PowerShell

[dpage]

Microsoft announced in October that they are deprecating VBscript; it will be come a "feature on demand" before being retired immediately.

To ensure that users do not have to install it in order to use our installers, and to avoid being caught off-guard when it's deprecated entirely, we should port all the existing VBscript helpers to PowerShell ASAP.

[sandeep-edb]

Noted. This task was already in the backlog, but it's priority is now increased and will be worked upon sooner. The InstallBuilder now offers actions to do certain tasks which were done through VB scripts, so will use them. For complex taks like initcluster we will rewrite into PowerShell.

[sandeep-edb]

This is partially done on all branches. Here is the commit for REL-12: 55b0bb3

[sandeep-edb]

The progress: on REL-17, except for initcluster.vbs all other VB scripts are migrated: https://github.com/EnterpriseDB/edb-installers/tree/REL-17/server/scripts/windows. On back branches these changes will be done soon.