Fix #507: Adding resources from multiple pages in the library now works

[seav]

Proposed changes in this pull request

• Fix Adding resources not on page 1 of library broken #507:
  • Add a script that on add-resources-from-library form submission, checks which resources are selected in the library regardless of pagination state and then dynamically insert hidden input fields corresponding to the selected resources. Checked checkbox input fields are also unchecked to prevent conflicts with the hidden fields. This script is located at resources/script_add_lib.html
  • Include this new script on all pages that use the resources/modal_add_lib.html template
  • Rename the resources/scripts.html template into resources/script_upload.html because there are now two resources-related scripts
• Other improvements:
  • Rename form_script template block into location_extra_script to reflect that this block is for additional scripts on a page with a Leaflet map. (I think this block was named form_script before in order to add form.media links but this block is no longer exclusive for that)
  • Remove the form_script block from party/relationship_detail.html since this page does not need any additional scripts or media
  • The location resource modal templates should have extended spatial/location_detail.html instead of spatial/location_wrapper.html

When should this PR be merged

• No dependencies needed for merging

Risks

• None foreseen

Follow-up actions

• None

[seav]

BTW, if in the future we switch to AJAX-powered DataTables, this new script needs to be adapted depending on how we solve the problem where connected resources in the library has not yet been loaded to the HTML table.