Host privacy implementation

[pan-]

Summary of changes

Refactoring of Privacy so it works with controller supporting LL private address resolution and LL private address generation. If not supported by the controller, generation is handled by the host.

The core of this change is the new PrivateAddressController class which handles private addresses generation, resolving list management and address resolution.

It replaces the PAL previously splitted between the SecurityManager and the Gap PAL.

State:

• Host private address generation
• Host private address resolution
• Controller address generation
• Private address when advertising
• Private address when scanning
• Private address when initiating
• Address resolution of advertising and scan report
• Address resolution of connection request

Preceding PR: #13475

Impact of changes

Migration actions required

Documentation

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Pull request type

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

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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

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Reviewers

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[mergify]

This PR cannot be merged due to conflicts. Please rebase to resolve them.

[pan-]

This is a feature branch and it will moved, we're merging this work now and provide remaining features in next PRs.

[pan-]

Review of this work was here: https://github.com/pan-/mbed/pull/8