2705 appimage script

[cakekoa]

What does this PR do?

Fixes part of #2705.

Updates the app image script to

PR Checklist

• Have you added an explanation of what your changes do and why you'd like to include them?
• Is the TravisCI build passing?
• Was the CHANGELOG.md updated to reflect the changes?
• Was the documentation framework updated to reflect the changes?
• Have you checked that you haven't introduced any duplicate code?

Testing Checklist

• Added relevant unit tests?
• Have you successfully tested your changes locally? Elaborate:

  Tested by {Running the Monkey locally with relevant config/running Island/...}

• If applicable, add screenshots or log transcripts of the feature working

[mssalvatore]

# Export TCl/Tk
export TCL_LIBRARY="${APPDIR}/usr/share/tcltk/tcl8.4"
export TK_LIBRARY="${APPDIR}/usr/share/tcltk/tk8.4"
export TKPATH="${TK_LIBRARY}"

These lines may no longer be needed in AppRun. They appear in the 3.7 appimage's AppRun but not 3.11.