Add OS-specific BAZELISK_HOME

[mzapotoczny]

BAZELISK_HOME should be set as absolute path, but all supported OSes use different folder structure. This might be a problem if we want to globally set BAZELISK_HOME for all developers.

Therefore we want to propose a change to add support for OS-specific BAZELISK_HOME, for example BAZELISK_HOME_WINDOWS.

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[mzapotoczny]

@fweikert could you take a look? Thanks in advance :)

[McAmun]

@fweikert - could you please have a look on that change ?

[McAmun]

@katre can you maybe help here ?

[McAmun]

@fweikert any update on this ?

[McAmun]

@fweikert @meteorcloudy - Can we get this merged please ? We would like to start using your official releases.

[fweikert]

@mzapotoczny thanks for this change, I took the liberty of resolving the merge conflict.