Files are opened, but not closed explicitly

[disconnect3d]

There are 5 instances when a file is opened to be read, but it is not closed explicitly. Because of it, there is a risk the file won't be closed and so a file descriptor limit can be exceeded (causing a program crash), depending on the given Python interpreter implementation.

Those instances can be found e.g. with ripgrep:

$ rg open
Apps.py
32:            files['binary'] = open(binary, 'rb')
43:            files['binary'] = open(binary, 'rb')

CustomConfigurationProfiles.py
23:        files = {'mobileconfig': open(mobileconfig, 'rb')}
39:            files['mobileconfig'] = open(mobileconfig, 'rb')

PushCertificate.py
23:        files = {'file': open(file, 'rb')}

Those cases should be changed to use the with statement so they explicitly .close() the file when the function returns or when an exception is thrown.

[rickheil]

Re-opening, see context in #34 for what needs to be done still.