Remove dependency on relay selector from tunnel actor

[pronebird]

Currently RelaySelectorResult (a part of RelaySelector module) is used across different parts of tunnel manager <-> tunnel actor.

RelaySelectorResult itself is produced by RelaySelector and passed as is from tunnel manager into actor via IPC to initiate connection, here is how the data layout looks like:

struct RelaySelectorResult {
    var endpoint: MullvadEndpoint // endpoints, gateways, pubkey
    var relay: REST.ServerRelay // Lotta info about relay returned from API
    var location: Location // Geo location
}

Then over time the tunnel manager receives a slice of that data via PacketTunnelRelay as it polls tunnel status:

struct PacketTunnelRelay { // PacketTunnelCore
    let ipv4Relay: IPv4Endpoint
    let ipv6Relay: IPv6Endpoint?
    let hostname: String
    let location: Location
}

In reality however, actor does not need the entire RelaySelectorResult, it would be enough to receive a type holding the following info instead:

struct SelectedRelay {
    var endpoint: MullvadEndpoint
    var hostname: String
    var location: Location
}

Changes

• Replace RelaySelectorResult with SelectedRelay in IPC/Actor interaction and subsequently removes dependency on RelaySelector in the actor.
• Pass NextRelay type instead of RelaySelectorResult? via reconnectTunnel() IPC method.

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This change is 

[linear]

IOS-339 Remove dependency on relay selector from tunnel actor

RelaySelectorProtocol – a requirement of PacketTunnelActor relies on RelaySelectorResult type exported from RelaySelector target.

We don't use all of the information provided byRelaySelectorResult but also we'd like to keep actor isolated from concrete implementation of relay selector.

So introducing a type with stricter requirements and exposing it from PacketTunnelCore could help remove the extra dependency and tighten up the architecture. For example:

struct SelectedRelay {
    var endpoint: MullvadEndpoint
    var hostname: String
    var location: Location
}

[buggmagnet]

Reviewed 12 of 19 files at r1, 7 of 7 files at r2, all commit messages.
Reviewable status: 19 of 20 files reviewed, 2 unresolved discussions (waiting on @pronebird)

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ios/MullvadVPN.xcodeproj/project.pbxproj line 2672 at r2 (raw file):

			isa = PBXGroup;
			children = (
				5819ABC22A8CF02C007B59A6 /* TunnelAdapterProtocol.swift */,

Nit
Can we reorder those files to be in alphabetical order ?

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ios/PacketTunnelCore/IPC/PacketTunnelOptions.swift line 18 at r2 (raw file):

        case selectedRelay = "selected-relay"

        /// Option key that holds the `NSNumber` value, which is when set to `1` indicates that

nit

        /// Option key that holds an `NSNumber` value, which, when set to `1` indicates that
        /// the tunnel was started by the system.

[pronebird]

Reviewed 1 of 7 files at r2.
Reviewable status: 17 of 20 files reviewed, all discussions resolved (waiting on @buggmagnet)

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ios/MullvadVPN.xcodeproj/project.pbxproj line 2672 at r2 (raw file):

Previously, buggmagnet wrote…

Nit
Can we reorder those files to be in alphabetical order ?

Done but keep in mind that this change might lead likely to merge conflicts in outstanding PRs.

---

ios/PacketTunnelCore/IPC/PacketTunnelOptions.swift line 18 at r2 (raw file):

Previously, buggmagnet wrote…

nit

        /// Option key that holds an `NSNumber` value, which, when set to `1` indicates that
        /// the tunnel was started by the system.

Done.

[buggmagnet]

Reviewed 1 of 19 files at r1, 2 of 2 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[rablador]

Reviewed 13 of 19 files at r1, 5 of 7 files at r2, 2 of 2 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[buggmagnet]

Reviewed 2 of 2 files at r5, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved