ruleset with absolute path cannot be added

[Matthias Ronge]

If you try to add a ruleset in the “Create new rule set” dialog and enter the full file path, e.g. “D:\Goobi\Goobi_Data\rulesets\gdz.xml”, there is a misleading error message that simply says: “The given ruleset file cannot be found.” This also happens when the file really exists on the given path. The message is actually true for Goobi because it internally combines the field input with the prefix from the configuration, but however, the error message could be improved, e.g. “The ruleset file "D:\Goobi\Goobi_Data\rulesets\D:\Goobi\Goobi_Data\rulesets\gdz.xml" cannot be found.” would make clear what had happened.

It is worth thinking about if we really only want to allow files to be added from a defined directory, and, if so, if it wouldn’t be better just to present a drop down list menu instead.