keepass: improvements

`*.desktop` file now:
 -  Refers to an icon.
 -  Is placed in the proper category (based on comparison with `keepassx2`.
 -  Has proper mime type (also based on comparison).

Also, now use `icoutils` to extract icons from the application ressouces
and transform them from `*.ico` to `*.png`. Created and used a generic
script that has the ability to move the extracted `*.png` to their
appropriate standard freedesktop location.

Tested this on nixos. `keepass` now has a icon and is categorized
in the same bin as `keepassx2`. The program still execute and
function prefectly.

pkgs/applications/misc/keepass/extractWinRscIconsToStdFreeDesktopDir.sh

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+# The file from which to extract *.ico files.
+#rscFile="./KeePass.exe"
+rscFile=$1
+
+# A regexp that can extract the image size from the file name.
+# sizeRegex='[^\.]+\.exe_[0-9]+_[0-9]+_[0-9]+_[0-9]+_([0-9]+x[0-9]+)x[0-9]+\.png'
+sizeRegex=$2
+
+# sizeReplaceExp='\1'
+sizeReplaceExp=$3
+
+# A regexp that can extract the name of the target image from the file name.
+# nameRegex='([^\.]+)\.exe.+'
+nameRegex=$4
+
+# nameReplaceExp='\1'
+nameReplaceExp=$5
+
+# out=./myOut
+out=$6
+
+# An optional temp dir. TODO: Generate it randomly by default instead.
+tmp=./tmp
+if [ "" != "$4" ]; then
+    tmp=$7
+fi
+
+
+
+rm -rf $tmp/png $tmp/ico
+mkdir -p $tmp/png $tmp/ico
+
+# Extract the ressource file's extension.
+rscFileExt=`echo "$rscFile" | sed -re 's/.+\.(.+)$/\1/'`
+
+# Debug ressource file extension.
+echo "rscFileExt=$rscFileExt"
+
+if [ "ico" = "$rscFileExt" ]; then
+    cp -p $rscFile $tmp/ico
+else
+    wrestool -x --output=$tmp/ico -t14 $rscFile
+fi
+    
+icotool --icon -x --palette-size=0 -o $tmp/png $tmp/ico/*.ico
+
+mkdir -p $out
+
+for i in $tmp/png/*.png; do
+  fn=`basename "$i"`
+  size=$(echo $fn | sed -re 's/'${sizeRegex}'/'${sizeReplaceExp}'/')
+  name=$(echo $fn | sed -re 's/'${nameRegex}'/'${nameReplaceExp}'/')
+  targetDir=$out/share/icons/hicolor/$size/apps
+  targetFile=$targetDir/$name.png
+  mkdir -p $targetDir
+  mv $i $targetFile
+done
+
+rm -rf $tmp/png $tmp/ico