EqualizerPresetSelector: Allow user to ajust the custom profiles order

This merge request brings some adjustments to the equalizer with:

• The custom equalizer profiles created by the user that can now be reordered in the list by selecting one of their leading actions.
• The rename and delete actions are that now added as trailing actions in order to be able to add a proper icon instead of a label and therefore match the implementation of the leading actions previously mentioned.
• Everything related to the custom equalizer profiles is now located in a proper dedicated file.

Leading actions

Trailing actions

(Feature request mentioned here: https://code.videolan.org/videolan/ios-support/-/issues/56873)