Make overrides of Mage_Core_Model_Resource_Db_Abstract::delete respect parent api

[midlan]

Description (*)

I fixed overrides of Mage_Core_Model_Resource_Db_Abstract::delete to respect parent api, which means:

• throw on error
• return $this

Fixed Issues (if relevant)

1. Fixes No throw when Mage_Admin_Model_User::delete fails #950

Manual testing scenarios (*)

Admin panel

1. make some constraint for admin_user table that not allow you delete record (e.g. foreign key referencing the table with RESTRICT rule ON DELETE)
2. go to admin panel and try delete some user, instead of green message that user was deleted, we should get red error message

API

There is changes also in API resource model, so we should test it also.

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All automated tests passed successfully (all builds are green)

[midlan]

@Flyingmana @sreichel review pls?

The base branch was changed.

[midlan]

It is BC break, labeled it and changed base branch to 20.0

[Sekiphp]

seems ok

for future compatibility, you should consider to replace catch of Exception to Throwable

[fballiano]

seems ok

for future compatibility, you should consider to replace catch of Exception to Throwable

I switched them

[fballiano]

But we should still add a note to the README in the "differences between v19 and v20"

[elidrissidev]

Updated the branch since the README's version was ancient and added the note to the README.

[github-actions]

Unit Test Results

1 files  ±0  1 suites  ±0   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
7 runs  ±0  7 ✔️ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 61f1a22. ± Comparison against base commit bc4b2cd.