Resize logo when uploading an image

[pierredup]

Is your feature request related to a problem? Please describe.
Issue partly related to #518, the size of the logo uploaded is very large and causes layout issues on the login page.

Describe the solution you'd like
Automatically resize the logo to a pre-defined value when uploading the logo to always fit in on the login page.

Describe alternatives you've considered
N/A

Additional context
N/A