Allow using AllItems view instead of default view for Sharepoint lists + change paging size

[ghost]

Some of the Sharepoint Lists we want to connect to have multiple views defined. At least on one list, it's default view is filtered (i.e. showing only non-completed values).

To transfer all the list's items (and not only those in the default view), we have to figure out the ID of AllItems.aspx, which always shows all items of said list.

Addition: We also had issues on larger Sharepoint lists taking a long time to load. Therefore a custom page size option has been added as well.

This PR therefore adds/changes the following:

python-connectors/sharepoint-online_lists/connector.json:

• additional advanced parameter Use All Items view (default: False)
• additional advanced parameter Page Size (default: 30 as would be without parameter as well)

python-lib/sharepoint_client.py:

• get_list_allitems_view_url() to build the URL required to download all available views for a given list
• get_list_allitems_view_id() to return a dictionary with view id if a non-default view is required
• get_view_query_string() to return a combined query string with all relevant parameters.
  • get a view id if available (default parameter)
  • use paging size if available (default parameter)
  • use query string returned by NextHref

python-connectors/sharepoint-online_lists/connector.py:

• Adjust get_next_page_query_string() to combine NextHref with default parameters

If you have any suggestions please let me know.

Best regards, Richard