Add new style for JITE

... JITE = Journal of Institutional and Theoretical Economics.

 * English style by German publisher
 * This style looks quite similar to the Chicago Manuals Style, but they don't mention anything in their style guide.
 * Update finanzarchiv.csl: Add pages in chapter/inproceeding (forgot before #1115)
I delete the second ISSN.

BTW do you know if (in theory) this ISSN could be assigned to a new journal or if it is somehow blocked? I am just curious, doesn't matter anyhow...