Closes#803
Implements host-style bucket addressing in the gateway. This feature can be enabled by running the gateway with the `--virtual-domain` flag and specifying a virtual domain name.
Example:
```bash
./versitygw -a user -s secret --virtual-domain localhost:7070 posix /tmp/vgw
```
The implementation follows this approach: it introduces a middleware (`HostStyleParser`) that parses the bucket name from the `Host` header and appends it to the URL path. This effectively transforms the request into a path-style bucket addressing format, which the gateway already supports. With this design, the gateway can handle both path-style and host-style requests when running in host-style mode.
For local testing, one can either set up a local DNS server to wildcard-match all subdomains of a specified domain and resolve them to the local IP address, or manually add entries to `/etc/hosts` to resolve bucket-prefixed hosts to the server IP (e.g., `127.0.0.1`).
niksis02
jonaustin09
