OSD summary stats improvements

[avsaase]

Changes:

• Max current and max power are now shown on the same line since they measure the same thing.
• Using osd_stats_min_voltage_unit = CELL, the average min cell voltage is shown instead of the total battery voltage. The default is BATTERY which is the current behavior.
• After the minimum battery or cell voltage, the current battery or cell voltage is shown. This follows the above setting. I find myself wanting to see the battery voltage directly after disarming, but this requires dismissing the stats. This change solves that issue.

I do not fully understand all the buff and statValuesX stuff but I managed to throw this together. There are a couple things I'm not yet happy with:

1. It would look nicer if max power was aligned more to the left when max current is less that 3 digits. The way I pasted these strings together feels a little janky to me. Is there a better way to do this?
2. When using 2 main battery voltage decimals the minimum voltage runs onto the / separating it from the current voltage. I tried accounting for this using displayWrite(osdDisplayPort, statValuesX + 4 + osdConfig()->main_voltage_decimals, top++, buff); but this doesn't work. Again it would be nicer to paste the strings together based on their actual length instead of some fixed number of characters.

I will later add the configurator side of this PR (also for osd_stats_energy_unit).

[avsaase]

Fixed both issues, also shifted all stats one character to the left:

[avsaase]

Is getBatteryRawVoltage() no longer updated when the disarm screen is shown? I am not 100% sure but I think it just gives the battery voltage at the moment of disarming.

[Jetrell]

@avsaase Does this allow DISARMED BY to now fit on the page, without being half cut off?

Another tidy up suggestion. Instead of the Amps, Watts and Power unit letters being alphabet characters.
Can you replace them with font characters

• A with 0x9a
• V with 0x06
• W with 0xae
  to keep more inline with the rest of the stats?

[avsaase]

@Jetrell For me DISARMED BY still falls off the bottom off the screen (completely) when using NTSC. I think having two max g-force lines is unnecessary but I assumed they are included for a reason. If not I'd like to remove the min/max Z g-force line.

Good idea about the symbols. I'll try to make that change this week.

[Jetrell]

I think having two max g-force lines is unnecessary but I assumed they are included for a reason. If not I'd like to remove the min/max Z g-force line.

I think so too. The G-force stats give a wrong readout most of the time, because they also record the touch down or landing G-force. Which is not useful at all.

[avsaase]

I would also be okay with removing both lines.

[OptimusTi]

why not show all available rows, wait a few seconds, clear the screen, and then show the remaining rows?