Bug 36221: (follow-up) Style and markup fixes

Bug 36221: (follow-up) Style and markup fixes

This patch makes several changes to make the updated forms more
consistent with how other pages work:

- Form labels should have ":" after them.
- Form fields should have a hint when they are required.
  - Required fields should not be indicated with an asterisk.
- In the OPAC, <select> should have a "form-select" class if the form is
  otherwise being styled with Bootstrap classes.
- Primary submit buttons should have a "btn btn-primary" class.
- The Font Awesome 6 icon for a delete operation is "fa-trash-can."
- Error messages should be wrapped in <div class="alert alert-warning">.
- All language strings in JS files should be wrapped in __('').
- Terminology: "Library" instead of "Branch," "Patron" instead of
  "Member."

Signed-off-by: Pedro Amorim <pedro.amorim@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>