Update text templates

Example request

{
  "offer": {
    "header": "{ANSCHREIBEN},<br/><br/>Some text before product table",
    "footer": "{IF}{GUELTIGBIS}{THEN}Offer is valid until: {GUELTIGBIS}{ELSE}{ENDIF}<br /><br />This form was created automatically",
    "disable_stationary": false
  },
  "order": {
    "header": "{ANSCHREIBEN},<br/><br/>Some text before product table",
    "footer": "{IF}{LIEFERADRESSE}{THEN}<strong>Delivery Address:</strong><br />{LIEFERADRESSE}{ELSE}{ENDIF}<br /><br />This form was created automatically",
    "disable_stationary": false
  },
  "invoice": {
    "header": "{ANSCHREIBEN},<br/><br/>Some text before product table",
    "footer": "{IF}{LIEFERADRESSE}{THEN}<strong>Delivery Address:</strong><br />{LIEFERADRESSE}{ELSE}{ENDIF}<br /><br />This form was created automatically\"",
    "disable_stationary": false
  },
  "delivery_note": {
    "header": "{ANSCHREIBEN},<br /><br />we deliver::<br /><br />{IF}{TRACKINGNUMMER}{THEN}Tracking-Number/n:{TRACKINGNUMMER}{ELSE}{ENDIF}<br />&nbsp;",
    "footer": "Dieses Formular wurde maschinell erstellt und ist ohne Unterschrift gültig.",
    "disable_stationary": false,
    "eu_delivery_note": "Tax-exempt according to §4 No.1 in conjunction with §6 ...",
    "export_delivery_note": "Tax-excempt in 3rd party country"
  },
  "credit_note": {
    "header": "{ANSCHREIBEN},<br /><br />some text:",
    "footer": "This form was created automatically",
    "disable_stationary": false
  },
  "purchase_order": {
    "header": "{ANSCHREIBEN},<br /><br />we order now:<br /><br />Our order number:: {BESTELLUNGBESTAETIGTABNUMMER}<br /><strong>Deliver Address: </strong>{LIEFERADRESSELANG}",
    "footer": "This form was created automaticallyThis form was created automatically"
  },
  "work_report": {
    "header": "{ANSCHREIBEN},<br /><br />we deliver following:",
    "footer": "This form was created automatically",
    "disable_stationary": false
  },
  "commission_credit_note": {
    "header": "{ANSCHREIBEN},<br /><br />,",
    "footer": "This form was created automaticallyThis form was created automatically"
  },
  "proforma_invoice": {
    "header": "{IF}{USTID}{THEN}Your VAT ID:{USTID}{ELSE}{ENDIF}<br />&nbsp;",
    "footer": "This form was created automatically",
    "disable_stationary": false
  },
  "misc": {
    "travel_expenses_without_letterhead": false,
    "footer_order_offer": "",
    "footer_order_offer_enabled": false,
    "footer_order_order": "",
    "footer_order_order_enabled": false,
    "footer_order_invoice": "",
    "footer_order_invoice_enabled": false,
    "footer_order_credit_note": "",
    "footer_order_credit_note_enabled": false,
    "footer_order_delivery_note": "",
    "footer_order_delivery_note_enabled": false,
    "footer_order_purchase_order": "",
    "footer_order_purchase_order_enabled": false,
    "footer_order_proforma_invoice": "",
    "footer_order_proforma_invoice_enabled": false
  }
}