This commit adds an 'index' field to the output of the `bt_list`
command. This is meant to be used with/for `bt_forget <index>`, which
requires an index of the device to forget - this helps clarify the index
of each device.

This is the maximum amount that malloc can currently allocate in a
single allocation.

Reviewed-on: https://codeberg.org/cool-tech-zone/tangara-fw/pulls/257

When `CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS` is not set, the FreeRTOS
scheduler will not keep track of task runtime statistics, and the `tasks`
command on the console will show `nan%` for the usage.

This adds a recommendation for the user to enable the `...STATS` config in
their build, and also updates the guidance for `configUSE_TRACE_FACILITY`
to point at the supported `sdkconfig.local` configuration pathway, instead
of pointing at the `#define` that's deeper in the configuration stack.

Also, the sampling period is dropped from 2.5s to 10ms when the runtime
stats are not enabled; given that we're not measuring any usage, it's not worth
sleeping any longer than that. We might even be able to drop to zero?

`std::sort` expects a comparator that returns `a < b`. Flipping this to `a >= b`
would normally be fine to reverse the order, but floats behave weirdly with NaN.

Instead of flipping the comparator, this uses the reverse-iterators to reverse
the sort order of the tasks, and returns to an `a < b` comparator.

Mostly for debugging, but also u can toggle fast charging off and on now