Enable all 8 layers and update mapping row layout

[MarqueIV]

Simple layout and firmware change to fully enable eight layers

Firmware Changes

• Change NLAYERS from 4 to 8

Web config changes

Live Demo: https://markdonohoe.com/remapper

• Combined the Input/Output columns into a single column (col-5) with equal-width buttons (w-50) to make room for the wider layers column
• Expand layers column from col-3 to col-4 to fit 8 layer checkboxes
• Unhide layers checkboxes 4-7 in both the mapping template and unmapped passthrough settings
• Increased the overall width of the page from 720 to 880 to accommodate the new columns. (I also simplified the min/max logic at the root container so it was no longer needed on the inside div.)

Note: NLAYERS above seems to be used for 'safety' logic regarding layer-switching mappings for cases where values on target layers aren't properly set in a configuration. However both the UI and the CLI tools properly create configurations that avoid this caveat, thus seemingly making this check seem redundant/unnecessary. However I am not sure if there are other ways to load configurations where such correctness isn't guaranteed, so to keep the firmware resilient, it makes sense to leave the check in place, hence updating the value here.

Testing

I have been running this with the latest firmware for a few months now with very complex configs and have not had any issues so far. Overall it appears to be quite stable.

Screenshots