[FEAT] year option in formats under the disk module

[Kingproone]

Description

I like that for some time there is a way to display days since install built in with the {days} variable, but I'd like to see this in years.
Maybe there is a way to do this with the available options that I have yet to discover, in the meantime I have a huge spagetti that does this:

    {
        "type": "command",
        "key": "   System  ",
        "text": "birth_install=$(stat -c %W / 2>/dev/null || stat -f %B / 2>/dev/null); if [ -z \"$birth_install\" ] || [ \"$birth_install\" -eq 0 ]; then birth_install=$(find / -maxdepth 0 -printf '%T@' 2>/dev/null); fi; current=$(date +%s); time_progression=$((current - birth_install)); days_difference=$((time_progression / 86400)); years_difference=$(awk \"BEGIN {printf \\\"%.2f\\\", $days_difference/365}\"); echo \"$years_difference years ($days_difference days)\"",
        "keyColor": "white"
    },

output:
System 1.58 years (576 days)

with the {year} it could look something like
{
"type": "disk",
"key": "Os Age",
"folders": "/",
"format": "{years} years",
},
this would only show the year, to show the days it was calculated from after it, like the spaghetti, #482 would need resolving
"format": "{years} years {days} days", would probably say the year and the remaining days, and not a rational number

Motivation

clean up the huge spaghetti I have to something leaner

Additional context

No response

[CarterLi]

Please test

[Kingproone]

All the options work on my end!
I have this line: "format": "{years} year and {days-of-year} days ({years-fraction} years)",
Which correctly prints: 1 year and 214 days (1.59 years)

In the wiki -> json chema -> disk, I can't seem to find "years-fraction", "years", "days-of-year" mentioned under the available formats.