use pre-generated ssh key

use pre-generated id_rsa.pub if exist
change UAC level

chagen UAC level for running under msys
is Admin really required?
Merge pull request #5 from filepang/feature/change-uac-level

change UAC level
Merge pull request #4 from filepang/feature/use-pre-genereated-ssh-key

use pre-generated ssh key 
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Edit after merge to check for id_rsa insead of id_rsa.pub
Checking for both: Public & Private Key

Checking for both: Public & Private Key, because we need to send the public Key to Gitlab and need the privat Key later to connect to the Git Server