Remove deprecated code

[cydanil]

Description

This PR fixes issues found in code analysis, mostly relating to the deprecated tempfile.mktemp.
Some deprecated code was also removed: not only are they broken, but have been already replaced by tests run by the CI (#2 .)

How Has This Been Tested?

The tests, as well as ensuring that each of the touched functionalities each keep working as intended within the application.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[lgtm-com]

This pull request introduces 3 alerts and fixes 17 when merging 0d3be90 into 3f872a4 - view on LGTM.com

new alerts:

• 3 for Unused import

fixed alerts:

• 7 for Insecure temporary file
• 2 for Unused import
• 2 for Clear-text logging of sensitive information
• 1 for Non-callable called
• 1 for Unused local variable
• 1 for Unreachable code
• 1 for Suspicious unused loop iteration variable
• 1 for Module is imported with 'import' and 'import from'
• 1 for Redundant assignment

[lgtm-com]

This pull request introduces 1 alert and fixes 19 when merging f97db2c into 3f872a4 - view on LGTM.com

new alerts:

• 1 for Unused import

fixed alerts:

• 7 for Insecure temporary file
• 3 for Unused import
• 2 for Clear-text logging of sensitive information
• 1 for Wrong name for an argument in a call
• 1 for Non-callable called
• 1 for Unused local variable
• 1 for Unreachable code
• 1 for Suspicious unused loop iteration variable
• 1 for Module is imported with 'import' and 'import from'
• 1 for Redundant assignment

[lgtm-com]

This pull request fixes 28 alerts when merging 4949552 into 3f872a4 - view on LGTM.com

fixed alerts:

• 12 for Unused import
• 7 for Insecure temporary file
• 2 for Clear-text logging of sensitive information
• 1 for Wrong name for an argument in a call
• 1 for Non-callable called
• 1 for Unused local variable
• 1 for Unreachable code
• 1 for Suspicious unused loop iteration variable
• 1 for Module is imported with 'import' and 'import from'
• 1 for Redundant assignment