Use X-API-Key in Gluetun client and remove non-existing WireGuard endpoints

[Rehpotsirhc-z]

What does this PR do?

The Gluetun client authenticated with Authorization: Bearer <key>, but Gluetun reads the API key from the X-API-Key header. Thus, the VPN card only worked when there was no key.

Also removed the /v1/wireguard/status and /v1/wireguard/portforwarded endpoints, which do not exist. The WireGuard and OpenVPN were both underneath the /v1/openvpn endpoint in the older versions. Since they were both under one endpoint anyway, the protocol selector is redundant and was removed.

Type of change

• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change (requires a migration plan - see CONTRIBUTING.md golden rule [Feature] Would love Real-Debrid Client support #3)
• Documentation only

Definition of Done checklist

See CONTRIBUTING.md for the full list.

• The feature works end-to-end, tested manually in a running container
• No console.log, dd(), var_dump, TODO, FIXME leftover
• Comments are in English
• Zero credentials in code, commits, logs, or docs
• At least one unit test for new business logic (N/A)
• If this is a bug fix: a regression test that reproduces the bug is included
• make check passes locally
• If an entity was modified: a new migration is committed (N/A)
• CHANGELOG.md updated under [Unreleased]
• README.md updated if user-facing behaviour changed (N/A)

Notes for the reviewer

• Sorry if the test file is bad.
• I tested manually on the latest Gluetun container, but not on any older versions.