[media] docs-rst: add tabularcolumns to all tables

LaTeX doesn't handle too well auto-width on tables, and ReST
markup requires an special tag to give it the needed hints.

As we're using A4 paper, we have 17cm of useful spaces. As
most media tables have widths, let's use it to generate the
needed via the following perl script:

my ($line_size, $table_header, $has_cols) = (17.5, 0, 0);
my $out;
my $header = "";
my @widths = ();
sub round { $_[0] > 0 ? int($_[0] + .5) : -int(-$_[0] + .5) }
while (<>) {
	if (!$table_header) {
		$has_cols = 1 if (m/..\s+tabularcolumns::/);
		if (m/..\s+flat-table::/) {
			$table_header = 1;
			$header = $_;
			next;
		}
		$out .= $_;
		next;
	}
	$header .= $_;
	@widths = split(/ /, $1) if (m/:widths:\s+(.*)/);
	if (m/^\n$/) {
		if (!$has_cols && @widths) {
			my ($tot, $t, $i) = (0, 0, 0);
			foreach my $v(@widths) { $tot += $v; };
			$out .= ".. tabularcolumns:: |";
			for ($i = 0; $i < scalar @widths - 1; $i++) {
				my $v = $widths[$i];
				my $w = round(10 * ($v * $line_size) / $tot) / 10;
				$out .= sprintf "p{%.1fcm}|", $w;
				$t += $w;
			}
			my $w = $line_size - $t;
			$out .= sprintf "p{%.1fcm}|\n\n", $w;
		}
		$out .= $header;
		$table_header = 0;
		$has_cols = 0;
		$header = "";
		@widths = ();
	}
}
print $out;

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>