- post list view gadget and details

- the json form is built from the form definition (hardcoded for now) and the context-document info
- only on post view gadget for now

- web site and pages
- changes in jio configuration

1. a inventory report module is added which user can add inventory report


2. in inventory report,  user should put information such as Owner, Warehouse... then call calculate product stock action


3. one line per product is then added automatically with current total quantity and total asset price


![Screenshot_2018-12-12_at_17.42.24](/uploads/98f8a4af66faadfdfd1d99b4400ff687/Screenshot_2018-12-12_at_17.42.24.png)


/reviewed-on nexedi/erp5!806

if i have a url like:
https://erp5xxx/form_idxxx?relative_item_relative_url=item_module/7817

with the old way, form id will be 7817

/reviewed-on nexedi/erp5!824

According to pep-0263, python scripts can define encoding magic on
first or second line.
If we use for example such a script:

```python
  # coding: utf-8
  return "héhé"
```

then using .read() was wrong, because it return the script with headers,
ie:

```python
  ## Script (Python) "test_coding"
  ##bind container=container
  ##bind context=context
  ##bind namespace=
  ##bind script=script
  ##bind subpath=traverse_subpath
  ##parameters=
  ##title=
  ##
  # coding: utf-8
  return "héhé"
```

so the coding magic is no longer in first line and pylint complains
with error like:

Cannot decode using encoding "ascii", unexpected byte at position 11 (invalid-encoded-data)]

/reviewed-on nexedi/erp5!825

only calculate exchange rate if necessary
use transaction cache
make getExchangeRate as local function

remove useless test_21
update test_20 with various packing list