storage_abstraction: deprecated since Mbed OS 5.5 and now removed

[VeijoPesonen]

Summary of changes

Removes deprecated API's under hal/storage_abstraction and the folder itself. Only target which had implemented the functionality was K64F and the implementation gets removed with this PR.

Impact of changes

Removes deprecated storage_abstraction API.

Migration actions required

Migration not possible. Developers who were relying on this API should study Mbed OS Storage documentation.

Documentation

---

Pull request type

[] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[X] Major update (Breaking change E.g. Return code change / API behaviour change)

---

Test results

[] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

---

Reviewers

@SeppoTakalo
@bulislaw
@ARMmbed/team-nxp

---

[0xc0170]

CI started

[mbed-ci]

Test run: FAILED

Summary: 1 of 11 test jobs failed
Build number : 1
Build artifacts

Failed test jobs:

• jenkins-ci/mbed-os-ci_cloud-client-pytest

[teetak01]

@0xc0170 can you re-run the client-tests?

[0xc0170]

Client tests restarted

[0xc0170]

@bulislaw review please, this is otherwise ready for integration