Render a document detailed view with document even if there's a library without pickup location in the organisation

[iGormilhit]

Describe the issue
If, inside a given organisation, there's a library with locations, but none being a pickup location, then a reader cannot load any document detailed view with item of this organisation, because the system fails to populate the request button dropdown menu.

To Reproduce
Steps to reproduce the behavior:

1. As a librarian, create a library with location, but without any pickup location. Edit: a library without location provides the same bug. But if you set one location as a pickup location, removing it does not always result with the same error.
2. As a reader, log in the system and try to load a document detailed view with items.
3. You should get an internal server error.
4. In the log, you should see something like the following:

ERROR in app: Exception on /cantonal/documents/12867 [GET]
Traceback (most recent call last):
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/invenio_records_ui/views.py", line 205, in record_view
    return view_method(pid, record, template=template, **kwargs)
  File "./rero_ils/modules/documents/views.py", line 82, in doc_item_view_method
    viewcode=viewcode
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/templating.py", line 140, in render_template
    ctx.app,
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/flask/templating.py", line 120, in _render
    rv = template.render(context)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/jinja2/asyncsupport.py", line 76, in render
    return original_render(self, *args, **kwargs)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/jinja2/environment.py", line 1008, in render
    return self.environment.handle_exception(exc_info, True)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/jinja2/environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/invenio/.local/share/virtualenvs/src-Z_EJbJTQ/lib/python3.6/site-packages/jinja2/_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "/invenio/src/rero_ils/modules/documents/templates/rero_ils/detailed_view_documents.html", line 20, in top-level template code
    {% from 'rero_ils/macros/macro.html' import dl, dl_dict, div_json %}
  File "/invenio/src/rero_ils/templates/rero_ils/page.html", line 27, in top-level template code
    {%- block outer_body %}
  File "/invenio/src/rero_ils/templates/rero_ils/page.html", line 33, in block "outer_body"
    {%- block body_inner %}
  File "/invenio/src/rero_ils/templates/rero_ils/page.html", line 37, in block "body_inner"
    {%- block page_body %}
  File "/invenio/src/rero_ils/templates/rero_ils/page.html", line 39, in block "page_body"
    {%- block body %}
  File "/invenio/src/rero_ils/modules/documents/templates/rero_ils/detailed_view_documents.html", line 38, in block "body"
    {%- block record_body %}
  File "/invenio/src/rero_ils/modules/documents/templates/rero_ils/detailed_view_documents.html", line 283, in block "record_body"
    {{ location.get_library().name }}
jinja2.exceptions.UndefinedError: 'None' has no attribute ‘get_library'

Expected behavior
The document detailed view rendering should succeed, but without pickup location for a give library in the request button dropdown menu.

Software version
ils.test.rero.ch, v0.5.1

ilsdev.test.rero.ch, 9aa529c

Additional information

When creating the first location of a library, the pickup location check box should be activated, without the possibility of deactivating it, until there's another pickup location for this library.