Add missing resolution slider to video settings - Issue #1380

[akrossu]

Issue

• Please add the resolution slider to the settings #1380

Description

• Adds a simple slider element in Video Settings to adjust the full-screen resolution.

Known Issues

• Does not dynamically set resolution without having to un-fullscreen and re-fullscreen.
• Does not display resolution when changing settings but displays the settings index value such as 0 - 100 possible resolutions.

Thank you to this pr by Madis0(#957) I was able to get a foot in the door with the issue.

I am aware this is planned for 0.5.0, however, I was very bored and wanted to make my first forked pull request

[douira]

If there is still interest in this, the branch this is targeting needs to be changed and then it could be reopened. This was only closed because branches were consolidated which resulted in PRs targeting those branches being closed automatically. However, if this PR is outdated or obsolete for other reasons it can just stay closed as it is.