UI optimization - migrate audio and display fixes

[wizmo2]

This PR is aimed at freeing up and fixing some minor display issues by

• Removing audio setup from webapp (allows easier customization in standard builds)
• fixes some button displays
• some minor formatting changes to address latest bootswatch issues and makes re-skinning simpler

Partition	Current with UI	Current w/o UI	This PR with UI	This PR w/o UI
recovery.bin	1319584	1295856	1296432	1269680
squeezlelite.bin	2666048	2640768	2647584	2614576

This is the first in a series of potential improvements. The next offers gains by moving more UI options to OTA only. It saves significant space in both the 'with and 'w/o' CONFIG_UI. (EDIT: I'm at 1263520 | 2642896 with full UI in OTA mode)

P.S. You will need to rebuild the webapp

[sle118]

@wizmo2 I am in the process of refactoring the complete configuration component and rewriting it from the ground up. Please hold on your contributions in that area because the overall design is likely to change drastically at a very low level and this will open the door to unforeseen possibilities.

This is a starting point for a revamped configuration UI that will leverage the new capabilities and also that will be a complete paradigm shift.

If you are interested, we can open a discussion on the subject and exchange ideas on the future of the UI. I will do my best to commit the first draft of the configurator component, which will be the basis of the future configurator engine (CE).

But at this point, I suggest you hold on to your changes as I'm also gearing towards a different approach to the UI that will offload the ESP32 from the majority of the UI burden