Change sidebar load formatting to be consistent.

[Murph9000]

round() is not a good function to use for formatting, as it produces inconsistent results by truncating trailing zeroes. printf() produces consistent results with an appropriate format.

The format string used here is equivalent to library/uptime.c in procps, producing output equivalent to /usr/bin/uptime on Debian.

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What does this PR aim to accomplish?:

The system load shown in the web sidebar has inconsistent formatting, in that trailing zeroes are stripped. By long standing convention, Unix/Linux load average is presented as number rounded to 2 decimal places. Breaking from this convention can be viewed as visually ugly to veteran users; and potentially confusing for novices who may think something extra is being conveyed by the variation in formatting.

How does this PR accomplish the above?:

This moves the formatting being performed by round(), which is not intended to be used for visual formatting, to vprintf(). There is no need to round the numbers being passed around within the scripts, it is sufficient to use the automatic rounding provided by vprintf(). This change makes the load in the sidebar consistent with the output from /usr/bin/uptime on Debian (which is, in turn, consistent with the historical Unix uptime command).

Link documentation PRs if any are needed to support this PR:

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[PromoFaux]

PR no longer relevant as php has been removed in development branches in preparation for v6 release