Fixes missing wmic command output running refine.bat if Powershell

[thadguidry]

Fixes problem where if refine.bat is run from a dev environment or PS, that the wmic command is not found and doesn't provide free memory amount in megabytes.

PS E:\GitHubRepos\OpenRefine> ./refine
'wmic' is not recognized as an internal or external command,
operable program or batch file.
-------------------------------------------------------------------------------------------------
You have M of free memory.
Your current configuration is set to use 1400M of memory.
OpenRefine can run better when given more memory. Read our FAQ on how to allocate more memory here:
https://openrefine.org/docs/manual/installing\#increasing-memory-allocation
-------------------------------------------------------------------------------------------------
Java 21 (21.0.5)
05:57:02.913 [            refine_server] Java runtime version 21.0.5+11-LTS from java.home: E:\Program Files\Eclipse Adoptium\jdk-21.0.5.11-hotspot (0ms)

Changes proposed in this pull request:

• Adds new PS Powershell? check at the beginning of refine.bat to use PS method of checking free memory of the system.

[thadguidry]

@wetneb I tested this and works great either running from cmd.exe or PowerShell now.

PS E:\GitHubRepos\OpenRefine> ./refine
-------------------------------------------------------------------------------------------------
You have 46140M of free memory.
Your current configuration is set to use 1400M of memory.
OpenRefine can run better when given more memory. Read our FAQ on how to allocate more memory here:
https://openrefine.org/docs/manual/installing\#increasing-memory-allocation
-------------------------------------------------------------------------------------------------
Java 21 (21.0.5)
05:54:11.476 [            refine_server] Java runtime version 21.0.5+11-LTS from java.home: E:\Program Files\Eclipse Adoptium\jdk-21.0.5.11-hotspot (0ms)
05:54:11.479 [            refine_server] Java VM: Eclipse Adoptium OpenJDK 64-Bit Server VM 21.0.5+11-LTS mixed mode, sharing (3ms)
05:54:11.480 [            refine_server] Starting Server bound to http://127.0.0.1:3333 (0ms)
05:54:11.480 [            refine_server] refine.memory size: 1400M JVM Max heap: 1400.0 MBytes (0ms)
05:54:11.515 [            refine_server] Initializing context: '/' from 'E:\GitHubRepos\OpenRefine\main\webapp' (35ms)
05:54:12.766 [                   refine] Starting OpenRefine 3.10-SNAPSHOT [TRUNK] ... (1250ms)
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