Task/Issue URL:https://app.asana.com/0/1199230911884351/1207175016813446/f

**Description**:This PR includes all changes relating to [this tech design
sub-task](https://app.asana.com/0/0/1207199754528648/f). Specifically:

Task/Issue URL: https://app.asana.com/0/0/1207231867963535/f
Tech Design URL: https://app.asana.com/0/0/1207198317317333/f
CC:

**Description**:
1. Moves the existing XPC interface ("DataBrokerProtectionScheduler")
from the scheduler into the BackgroundAgentManager
2. Renames said manager to AgentManager
3. Renames the XPC interface to DataBrokerProtectionAgentInterface
4. Completely changes the composition of the interface, separating it
out into two different protocols: DataBrokerProtectionAgentAppEvents,
DataBrokerProtectionAgentDebugCommands
5. As those protocols imply, changes the XPC interface methods to be
events based, to move decision making from the main app to the agent.
Except for the debug commands, which are now clearly separated as for
debugging purposes only.
6. Removes two of the many XPC layers since they were operating solely
as a passthrough (i.e. boilerplate for nothing)
7. Uses protocol composition to further cut down on the repetition in
those layers
8. Changes LoginItemScheduler to rather than be a class, a protocol that
inherits the AgentInterface
9. Removes existing completions from the XPC interface since they were
unused
10. Replaces them with new completions that are solely for reporting the
reliability of XPC

It still needs the pixels for #9, including clean up of the old pixels

**Steps to test this PR**:
1. Test DBP still works, particularly removing the login item, entirely
and starting fresh (since when testing at one point I managed to break
that)
2. Otherwise don't test too much since this PR is not intended to stand
alone/be merged into main as is.

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###### Internal references:
[Pull Request Review
Checklist](https://app.asana.com/0/1202500774821704/1203764234894239/f)
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)
[Pull Request
Documentation](https://app.asana.com/0/1202500774821704/1204012835277482/f)

Task/Issue URL: https://app.asana.com/0/0/1207231867963533/f
Tech Design URL: https://app.asana.com/0/0/1207199754528649/f

**Description**: This PR introduces `DataBrokerProtectionQueueManager` to manage state
and logic relating to the `OperationQueue` which runs DBP operations.

Task/Issue URL:
https://app.asana.com/0/1199230911884351/1207175016813449/f
Tech Design URL:
CC:

**Description**:
1. Move all userNotification related calls and anything else unrelated
to scheduling up a layer to the agent manager
2. Removes the existing scheduler, and moves the ActivityScheduler
management to a new class
3. Make a variety of changes to scheduler behavior, such as running all
the time (as long as theirs profile data), changing scheduler frequency
to 20 minutes, removes status publishing
4. Fixes us not deleting the login item when the user deleted their data
5. As part of that, removes the dataDeleted IPC method, since it's no
longer needed
5. Reworks the agent manager and associated dependancies so it can be
unit tested
6. Adds those unit tests.

Pixels are still outstanding
But everything else should be done now (integrating with Pete's latest
PR etc)

**Steps to test this PR**:
1. Generally test that DBP works, but not too thoroughly since we will
do that for the whole feature branch at once.

<!--
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If this PR isn't ready to be merged for whatever reason it should be
marked with the `DO NOT MERGE` label (particularly if it's a draft)
If it's pending Product Review/PFR, please add the `Pending Product
Review` label.

If at any point it isn't actively being worked on/ready for
review/otherwise moving forward (besides the above PR/PFR exception)
strongly consider closing it (or not opening it in the first place). If
you decide not to close it, make sure it's labelled to make it clear the
PRs state and comment with more information.
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---
###### Internal references:
[Pull Request Review
Checklist](https://app.asana.com/0/1202500774821704/1203764234894239/f)
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)
[Pull Request
Documentation](https://app.asana.com/0/1202500774821704/1204012835277482/f)

---------

Co-authored-by: Pete <[email protected]>

# Conflicts:
#	DuckDuckGo.xcodeproj/project.pbxproj
#	LocalPackages/DataBrokerProtection/Sources/DataBrokerProtection/Operations/DataBrokerJobRunner.swift
#	LocalPackages/DataBrokerProtection/Sources/DataBrokerProtection/Operations/DataBrokerOperation.swift

# Conflicts:
#	DuckDuckGo.xcodeproj/project.pbxproj
#	DuckDuckGoDBPBackgroundAgent/DataBrokerProtectionBackgroundManager.swift
#	LocalPackages/DataBrokerProtection/Sources/DataBrokerProtection/DebugUI/DataBrokerRunCustomJSONViewModel.swift
#	LocalPackages/DataBrokerProtection/Sources/DataBrokerProtection/Scheduler/DataBrokerProtectionScheduler.swift
#	LocalPackages/DataBrokerProtection/Tests/DataBrokerProtectionTests/Mocks.swift