Move reverb silder to advanced settings

**What is the current behaviour and why should it be changed?**

Currently, the reverb slider takes up a lot of space in the main mixer board. It is assumed that this could be mistaken as general volume slider. In order to simplify the UI, the reverb slider should go to advanced settings instead.

In future - if we support plugins, the reverb feature could be removed and replaced by custom reverb plugins.

**Describe possible approaches**

Move the slider to advanced settings.

**Has this feature been discussed and generally agreed?**

See: https://github.com/orgs/jamulussoftware/discussions/3341#discussioncomment-10576183
https://github.com/jamulussoftware/jamulus/discussions/2361#discussioncomment-10677859

ソースファイルもテストも指定されていません。まずミキサーボードのリバーブスライダーと詳細設定 UI を見つけ、次にそのスライダーがメインミキサーに表示されなくなり、詳細設定では引き続き利用できることを確認してください。

索引モデルが issue の本文から書いたものです。