Fix get_bloat for Windows and use PGPASSFILE

[marcohald]

Bug reports

Please include:

• Your operating system name and version
  Windows Server 2019
• Detailed steps to reproduce the bug

1. use more than 3 Postgres DBs
   Then the get_bloat crashes with "The command line is too long."

2. Set a System Environment Variable for the PGPASSFILE
   It get's overwritten by an empty String

Proposed changes

This commit fixes two issue.

1. The get_bloat executes psql for each database. This is necessary because otherwise it exceeds the maximum 8191 characters limit of windows https://learn.microsoft.com/en-us/troubleshoot/windows-client/shell-experience/command-line-string-limitation Which triggers the error "The command line is too long." I observed it with 3 databases

2. The PGPASSFILE Env varaible is only overwritten by the instance pg_passfile when it is not empty. In this way it is possible to use a system wide PGPASSFILE evnironment variable.

[si-23]

Hi,
thank you for uploading a PR.
Please resolve the merge conflicts.

[github-actions]

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[marcohald]

I have read the CLA Document and I hereby sign the CLA or my organization already has a signed CLA.

[si-23]

Hi,
I'm very sorry that I have to ask you again: Please can you rebase your PR?
We're are currently working on a similar topic: "Argument list too long" and we may include your PR in our changes.

I'm sorry for the inconvenience!
BG

[TimotheusBachinger]

Dear Checkmk Contributor! Unfortunately, we had to re-write our git-repo history, rendering your PR auto-closed. We will therefore rebase your PR onto the current master and reopen it again. Sorry for the inconvenience.

[TimotheusBachinger]

Dear Contributor. Unfortunately, we learned that re-opening a PR which was force-rebased, is not possible (see isaacs/github#361). Therefore we kindly ask you to create a new PR for your change. We apologize for the circumstances and will implement technical measures to prevent such incidents in the future.