Upgrade dependencies in preparation for release

See merge request !2894

This is a workaround for
#1335

The `js` feature was replaced by a configuration flag in [0.3.0], so
I've checked in a `.cargo/config.toml` for `tor-llcrypto` and
`tor-bytes` with `RUSTFLAGS` for selecting the `getrandom` backend to
use on wasm32.

[0.3.0]: https://github.com/rust-random/getrandom/blob/master/CHANGELOG.md#030---2025-01-25

We aren't affected by any of the breaking changes from [0.103.0].

[0.103.0]: https://github.com/rustls/webpki/releases/tag/v%2F0.103.0

In 0.27.0, strum's MSRV was bumped to 1.66.1, but that's okay because
ours is 1.77.

We aren't affected by any of its [breaking changes].

[breaking changes]: https://github.com/Peternator7/strum/blob/master/CHANGELOG.md#0270

Add test for keymgr interop with external tools like ssh-keygen

Closes #1455 and #1820

See merge request !2873

Closes #1455

Closes #1455 [PATCH 4(v3)/4]

Part of #1455 [PATCH 3(v3)/4]

Part of #1455

Closes #1455 [PATCH 4(v2)/4]

Part of #1455 [PATCH 3(v2)/4]

Part of #1455 [PATCH 2(v2)/4]

- Rework sshkeygen::ed25519_encoded to also work as replacement for
  sshkeygen::exists
- Drop sshkeygen::exists
- Rename sshkeygen::{ed25519_encoded -> sshkeygen_ed25519_strings}
- Pull out sshkeygen_ed25519_strings from mod sshkeygen
- Drop mod sshkeygen

_sigh_

Closes #1455 [PATCH 4/4]

Part of #1455 [PATCH 3/4]

Abstract of the test(s):

Encoded (key) A -> Decoded (key) A
Decoded A -> Encoded B
Encoded B -> Decoded B

Assert that Decoded A == Decoded B

Part of #1455 [PATCH 2/4]

Utils include:

- mod sshkeygen
- sshkeygen::exists - check if ssh-keygen is available
- sshkeygen::ed25519_encoded - generate encoded Ed25519 keys

Part of #1455 [PATCH 1/4]

ssh_key::{PrivateKey, PublicKey}::to_openssh requires feature alloc

TestSpecifier::new(prefix: ...) -> new(suffix: ...)

Prefix is given by TestSpecifier::path_prefix() which returns
const TEST_SPECIFIER_PATH = "..."

tor-proto: Fix possible bug when no hops are ready

See merge request !2885

fix compiling fs-misstrust on tvOS

See merge request !2890

tor-circmgr: Explicit type annotation

See merge request !2886

tor-keymgr: Implemented test improvements

Closes #1888

See merge request !2848

This commit adds an explicit type annotation to the learning_timeouts()
function, as leaving it out yielded an error while trying to compile
tor-circmgr in a project that had this crate deep down in its supply
chain.

examples: Version bump Tor browser in download-manager

See merge request !2888

Cleanups related to rpc configuration

Closes #1309 and #1830

See merge request !2887

tor-proto: simplify `ConfluxSet::circuit_action`

See merge request !2884

I also added an additional non-doc TODO comment.

Closes #1830.

Mark RPC stable, and revise READMEs for RPC crates.

Closes #1883

See merge request !2871