planet_stockpile.php: better default form values
planet_stockpile.php: better default form values

Since planets can only hold a certain amount of each good,
do not populate the form with default values that are greater
than the maximum the planet can hold.

This change makes the Stockpile page behavior consistent with
the Defense page.

hemberger/smr,hemberger/smr,smrealms/smr,hemberger/smr,smrealms/smr,hemberger/smr,smrealms/smr