Remove old getIdFromFilename for let admin can implement it himself

[hdsdi3g]

And migrate it to a brand new JSModule.
Test with:
mydmam-cli.bash jsinjava -class "hd3gtv.mydmam.pathindexing.IdExtractorFileName" -module IdExtractorFileName -method isValidId -args "<file name>"
and
mydmam-cli.bash jsinjava -class "hd3gtv.mydmam.pathindexing.IdExtractorFileName" -module IdExtractorFileName -method getId -args "<file name>"

Example code:

        getId: function(filename) {
            if (filename == null) {
                return null;
            }
            if (filename.length < 8) {
                return null;
            }
            var curchar;
            for (var pos = 0; pos < 8; pos++) {
                curchar = filename.charCodeAt(pos);
                if ((curchar > 47) && (curchar < 58)) {
                    // * from 0 to 9
                    continue;
                }
                if (((curchar == 83) || (curchar == 115)) && (pos == 0)) {
                    // * Start by "S" or "s"
                    continue;
                }
                return null;
            }

            return filename.substring(0, 8);
        },

And

        isValidId: function(filename) {
            if (filename == null) {
                return null;
            }
            if (filename.length < 8) {
                return null;
            }

            var curchar;
            for (var pos = 0; pos < 8; pos++) {
                curchar = filename.charCodeAt(pos);
                if ((curchar > 47) && (curchar < 58)) {
                    // * from 0 to 9
                    continue;
                }
                if (((curchar == 83) || (curchar == 115)) && (pos == 0)) {
                    // * Start by "S" or "s"
                    continue;
                }
                return false;
            }
            return true;
        },