Fix CWD for InstallCommandlet

[alfeilex]

Expected behavior

The installation commandlet ideasy -f install should also work when run outside «installation-location»\_ide itself (cd "$(dirname "$0")/..").

Actual behavior

When running ideasy install outside «installation-location»\_ide` , the `cdw` is the current path and when its not in `_ide` then wrong resolving results in invalid path, like «installation-location»_ide\bin\bin`.

Steps to reproduce

Run ``«installation-location»_ide\bin\ideasy.exe installor navigate inside the bin folder and runideasy -f install` there. Be sure that IDEasy is not installed on your system. Remove software/maven and also the env

Missing required file bin
Missing required file functions
Missing required file internal
Missing required file system
Missing required file IDEasy.pdf
Missing required file setup
IDEasy release is inconsistent at C:\projects\_ide\bin

A solution is that the cwd variable is cwd = IDE_ROOT/_ide

[hohwille]

See also oracle/graal#10773