Spanish translation update and general localization improvements

This update fixes some additional translation issues and adds polishment.

Also:

• Makes some additional contextual menu entries translatable instead of hardcoded.
• Makes the 'INI File' string in Folder options translatable instead of clunklily concatenating an uppercase extension + " " + "File" (string retrieved from a random menu item that just happens to have the same meaning in English). Some languages like Spanish reverse the word order ("Archivo INI"), with this little change now the string is constructed with a localizable printf ("%s File") and the translation is not longer hardcoded or awkwardly phrased.

(Not CC'ing aminekhaldi this time, tho)

It can probably subdivided in two commits, one for shell32 with code changes and other for the rest of .rc and hive changes.