Move variable moveDir into loop to prevent accumulation effects

In !221 (merged), the variable moveDir got an increased scope, since it was needed outside the specific scope. During that the mistake was made to initialize the variable outside the for-loop. The variable is for small corrections, but these corrections now are accumulated, which was not intended.

Initializing the variable at the beginning of the for-loop fixes the issue.

Closes #444 (closed)

Reviewer Checklist

Formatting

• the pre-build checks succeed

General code quality

• naming conventions are met (see .clang-tidy for detailed information)
• no static analyzer warnings in new code parts (e.g., use clang-tidy for checking)

General usability

• old versions of pet-files are still loadable

Only if changes in UI

• new elements are also saved and loaded from pet-file
• check if tab order is still correct
• all new SpinBoxes are promoted
• new keybindings added to Petrack::keyBindings()