Respect custom API endpoint when the api-override feature is enabled

[MarkusPettersson98]

This PR fixes an issue with the daemon not configuring the firewall correctly in case the api-override feature is enabled.

More specifically, this PR moves the responsibility for using overridden API endpoints for API calls from mullvad-api::rest to mullvad_daemon::api. This is in line with how the interaction between the two crates work for a normal release build , i.e. when the api-override feature is disabled.

This commit also removes the force_direct_connection, since it was always true when the api-override feature was enabled. This change also affects the Android client code. Since the flag does not exist in the mullvad-api or mullvad-jni rust crates anymore, it would be erroneous to try to serialize/deserialize the value in the Android client.

The boy scout rule was generously applied to mullvad_api::ApiEndpoint, since I found the logic of initializing it hard to read due to how intertwined it was with the #[cfg(feature = "api-override")] attribute.

Fixes DES-550

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This change is 

[albin-mullvad]

Reviewed 3 of 11 files at r1.
Reviewable status: 3 of 11 files reviewed, all discussions resolved

[dlon]

Reviewed 8 of 11 files at r1, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @MarkusPettersson98)

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mullvad-api/src/lib.rs line 164 at r1 (raw file):

        api.address = match address_var {
            Some(user_addr) => {
                let addr = user_addr.parse().unwrap_or_else(|_| {

Nit: Can't we just use .expect()?

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mullvad-api/src/lib.rs line 238 at r1 (raw file):

    /// [`Self::API_HOST_DEFAULT`] as default value if it does not exist.
    pub fn host(&self) -> String {
        self.host

Nit: Is it possible to return a &str using self.host.as_ref().unwrap_or(...)?

[linear]

DES-550 Firewall not always updated correctly if `api-override` is in use

[Pururun]

Reviewed all commit messages.
Reviewable status: all files reviewed, 3 unresolved discussions (waiting on @MarkusPettersson98)

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mullvad-api/src/lib.rs line 107 at r1 (raw file):

pub struct ApiEndpoint {
    /// An overriden API hostname. Initialized with the value of the environment
    /// variable `MULLVAD_API_HOSt` if it has been set.

Nit: This should be MULLVAD_API_HOST with a capital T right?

[MarkusPettersson98]

Reviewable status: 7 of 11 files reviewed, 3 unresolved discussions (waiting on @dlon and @Pururun)

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mullvad-api/src/lib.rs line 107 at r1 (raw file):

Previously, Pururun (Jonatan Rhodin) wrote…

Nit: This should be MULLVAD_API_HOST with a capital T right?

Yes, of course 🦅 👁️
Thanks!

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mullvad-api/src/lib.rs line 164 at r1 (raw file):

Previously, dlon (David Lönnhager) wrote…

Nit: Can't we just use .expect()?

Because I want to use format! in that case, clippy will issue a warning for the expect_fun_call lint 😊

https://rust-lang.github.io/rust-clippy/master/index.html#/expect_fun_call

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mullvad-api/src/lib.rs line 238 at r1 (raw file):

Previously, dlon (David Lönnhager) wrote…

Nit: Is it possible to return a &str using self.host.as_ref().unwrap_or(...)?

Yes, it proved to be possible! Thanks for pointing it out:)

[dlon]

Reviewed 4 of 4 files at r2, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @MarkusPettersson98 and @Pururun)

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mullvad-api/src/lib.rs line 164 at r1 (raw file):

Previously, MarkusPettersson98 (Markus Pettersson) wrote…

Because I want to use format! in that case, clippy will issue a warning for the expect_fun_call lint 😊

https://rust-lang.github.io/rust-clippy/master/index.html#/expect_fun_call

I see!

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mullvad-daemon/src/api.rs line 350 at r2 (raw file):

            log::warn!(
                "The `api-override` feature is enabled, but the API address \

This should not trigger a warning, IMO. It will do so for all dev builds.

[dlon]

Reviewed 1 of 1 files at r3, 1 of 1 files at r4, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @Pururun)

[dlon]

Reviewed 1 of 1 files at r5, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @Pururun)

[MarkusPettersson98]

Reviewable status: 10 of 11 files reviewed, 1 unresolved discussion (waiting on @dlon and @Pururun)

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mullvad-daemon/src/api.rs line 350 at r2 (raw file):

Previously, dlon (David Lönnhager) wrote…

This should not trigger a warning, IMO. It will do so for all dev builds.

Lowered the log-level to debug 😊

[dlon]

Reviewed 1 of 1 files at r6, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @Pururun)