Bug 33103: Add the ability to create vendor aliases

Bug 33103: Add the ability to create vendor aliases

This patchset is adding the ability to create aliases for vendors. It
will then be easier to search for vendors.

* new DB table aqbookseller_aliases(id, vendor_id, alias)
* new pair of Koha classes Koha::Acquisition::Bookseller::Alias[es]
* new method to retrieve the aliases from the vendor
Koha::Acquisition::Bookseller->aliases
* The api spec changes to allow aliases to be embeded on
GET /acquisitions/vendors
* Add/Delete alias when editing a vendor
* Display the aliases on the vendor show view
* Search vendors by aliases
* Display the aliases in the dropdown list of the vendors in the ERM
module

Test plan:
- Create a vendor, add it some aliases
- Edit the vendor, remove some aliases
=> Behaviour must be consistent
- Search the vendor in the acquisition module by its aliases
=> The vendor must be returned in the result
- Go to the ERM module, add a new agreement or license
=> Notice that the dropdown list of the vendors is displaying the
aliases, that make vendors searchable by their aliases

Signed-off-by: Jonathan Field <jonathan.field@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>