Remote Messaging Framework for macOS (duckduckgo#876)

Task/Issue URL: https://app.asana.com/0/72649045549333/1202913520695928/f

Description:
This change adds support for RMF on macOS.
* Remaining RMF functionality previously present in iOS codebase was moved to BSK
  (most importantly RemoteMessagingProcessing protocol).
* remoteMessaging feature flag was added.
* RemoteMessagingConfigMatcherProviding protocol was added – it's implemented by client apps
  to create and return the config matcher filled with current values of matching attributes.
* Support for platform-specific user attribute matchers was added. CommonUserAttributeMatcher was added
  to handle attributes that are the supported on both iOS and macOS. Mobile and Desktop user attribute matcher
  structs were added to support platform-specific attributes (currently it's only isWidgetInstalled for iOS).
* RemoteMessagingRequest was replaced with RemoteMessagingConfigFetcher that uses Configuration Store
  and supports Etags.
* All RMF tests (and mocks) were moved out of BrowserServicesKit(Tests) into RemoteMessagingTestsUtils
  and RemoteMessagingTests (that also mandated creating EmailTestsUtils).
* RemoteMessagingStore was updated to keep a reference to the database and create contexts on demand,
  to ensure it always gets the freshest data from the persistent store.

Bumped C-S-S to 6.0.0 (duckduckgo#880)

Add connection tester failure pixels (duckduckgo#881)

Task/Issue URL: https://app.asana.com/0/1206580121312550/1207743877093953/f

iOS PR: duckduckgo/iOS#3049
macOS PR: duckduckgo/macos-browser#2948

What kind of version bump will this require?: Patch

## Description

Adds pixels to track connection tester failures and recovery.  These should give us a better idea about how users are faring.

De-duplicate passwords on import (duckduckgo#869)

* Update account hashValue with new dedupe logic

* Expose password encryption function

* Revert "Update account hashValue with new dedupe logic"

This reverts commit b21c379.

* Add deduplicate subfeature

* Swiftlint

Privacy Dashboard refactor (duckduckgo#879)

Required:

Task/Issue URL: https://app.asana.com/0/1201392122292466/1207677104863315/f
iOS PR: duckduckgo/iOS#3038
macOS PR: duckduckgo/macos-browser#2943
What kind of version bump will this require?: Major

Description:

- remove old pixels,
- remove user behavior toast experiment,
- refactor Privacy Dashboard,
- add documentation,
- test Privacy Dashboard

Merge branch 'release/164.2.0-2'

Improve VPN logging logic (duckduckgo#877)

Task/Issue URL: https://app.asana.com/0/1206580121312550/1207223772590802/f

iOS PR: duckduckgo/iOS#3032
macOS PR: duckduckgo/macos-browser#2939

What kind of version bump will this require?: Major/Minor/Patch

## Description

Improves the logging logic for the VPN.

Fixes for Xcode16 (duckduckgo#864)

Task/Issue URL: https://app.asana.com/0/1199230911884351/1207655348648728/f
macOS PR: duckduckgo/macos-browser#2907

Update the Privacy Pro status attribute to use an array. (duckduckgo#878

)

Required:

Task/Issue URL: https://app.asana.com/0/1199333091098016/1207731341550989/f
iOS PR: duckduckgo/iOS#3033
macOS PR: duckduckgo/macos-browser#2940
What kind of version bump will this require?: Patch (technically the public API has not changed)

Description:

This PR updates the Privacy Pro status attribute to match an array instead of a string.