Before this commit:

- Product retrieval during import relied on exact name match and substring (ilike) search.
- Exact name search was case sensitive, so values like `Network Cable` would not match `Network cable`.
- Substring matching could return unrelated products (e.g. `Wireless bluetooth speaker` gets matched with
  `Wireless bluetooth speaker battery`), leading to unrelated matches.

After this commit:

- Exact name search is now case insensitive, allowing matches such as `Network Cable` and `network cable`.
- Substring based matching has been replaced with a similarity ratio (90%) to reduce false positives and improve matching reliability against customer database product names.

Technical:

- Replaced `=` with `=ilike` in the exact name search domain to make the lookup case insensitive.
- Similarity ratio is computed using Python's `difflib.SequenceMatcher` on product names, with a minimum threshold of 90% to qualify as a match.
- Added system parameter for configurable product name similarity threshold.

task-5951469

Forward-Port-Of: odoo/odoo#257452
Forward-Port-Of: odoo/odoo#252147

Issue:
--
The query created by the function '_compute_sale_order_ids' takes
around 20-40 seconds since its doing "WHERE" searches on millions
of stock.picking records

Fix:
--
Added an index to the "lot_id" field of the stock.move.line model.
(Already existing databases can be fixed by using the webshell)

Steps to recreate the issue:
--
1. Have around a million stock.picking records
2. Go to "Inventory/Products/Lots/Serial Numbers"
3. Select any existing record or create and save a new one
4. These actions will take around 20-40 seconds to complete

Before this commit:
--
Selecting or saving any 'stock.lot' takes around 20 seconds

After this commit:
--
Selecting or saving any 'stock.lot' takes around 1-4 second

Benchmark:
--
Benchmark test was done one a database with ~4000 stock.move records and
1.74 million stock.picking records
Opw-5459842
| Before this Commit | ~20 seconds
| After this Commit | **~1-4 seconds & Memory usage just a little bit higher

---
I confirm I have signed the CLA and read the PR guidelines at www.odoo.com/submit-pr

Forward-Port-Of: odoo/odoo#255255

### [IMP] databases: remove xmlrpc fallback for odoo.com

Since odoo.com migrated to 19.0, it will always support the json2 API, and XMLRPC support will be dropped on the next version.

In order to simplify the code and avoid subsequent requests in case of errors on the json2 API, the XMLRPC fallback is stripped off from `databases.api`.

In this commit, we only adapt the tests so that they don't test the fallback to XMLRPC when calling odoo.com. In the next commit, we will remove the dead code.

The configuration parameter `databases.odoocom_apiuser` is removed, as well as the corresponding field in the Settings page.

### [IMP] databases: remove xmlrpc fallback for odoo.com (fixup!)

With this second commit, we remove the dead code concerning the fallback to XMLRPC when calling odoo.com.

### [IMP] databases: use multidb routes to fetch KPIs on SaaS

When synchronizing KPIs from databases in the new Databases application, it takes a long time to make a RPC call to each database in the list.

With this commit, in the case of the SaaS, these calls are grouped by server to a dedicated route that will process the information faster, like the databases dashboard odoo.com/my/databases already does to fetch mail activities summary.

Task-id: [5167731](https://www.odoo.com/odoo/project.task/5167731)