I can't see how you can do well what you want; others more experienced may well have a trick to do it. Maybe something along the lines of:

my $x = "variable_name";
my $value = "value";
eval "\$$x = $value";
warn $@ if $@;
print $color1;
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Which works, but not under use strict.

My suggestion would be to change your approach to use a hash. This would greatly simplify things.

my %config;

# use database (DBI) to read key / values into hash
# ...
$config{color1} = "red";

print $config{color1};
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Update: Just re-read your question. You want a way to provide access to the %config hash on each page. You could use a module to do this, exporting the %config hash.