Route service clients through shared HTTP setup (#7639)

* storage: route OpenDAL through HTTP client

OpenDAL 0.58 requires applications to provide an HTTP transport. Its
default installer creates a standalone client, bypassing Vaultwarden
DNS, redirect, proxy, timeout, and request configuration.

Build the client through the internal HTTP interface and inject it into
OpenDAL's public reqwest transport.

* http: honor block setting on redirects

Clients can disable host blocking for administrator-configured private
services. DNS resolution honors this setting, but the redirect policy
still performs config-backed host checks.

Capture the setting in the redirect policy and skip those checks when
blocking is disabled. This also avoids re-entering CONFIG when a remote
configuration request is redirected during startup.

* http: make DNS setup bootstrap-safe

Remote configuration can require an HTTP client while CONFIG is still
initializing. Building the DNS resolver currently reads
CONFIG.dns_prefer_ipv6(), so loading an S3-backed config can deadlock.

Build one resolver without consulting CONFIG. Order addresses for each
lookup using the merged setting when available, falling back to the
environment and then IPv4-first during bootstrap.

* aws: use internal HTTP client

The AWS SDK connector builds a raw reqwest client, bypassing
Vaultwarden TLS, DNS, redirect, proxy, timeout, and request setup.

Construct it through the internal HTTP client interface and retain the
standard ten-second request deadline. Permit private AWS metadata and
service endpoints by disabling non-global IP blocking.

Preserve timeout errors when adapting reqwest failures to the AWS SDK so
the runtime receives the correct connector error category.

* Added comment for the prefer IPv function

Signed-off-by: BlackDex <black.dex@gmail.com>

---------

Signed-off-by: BlackDex <black.dex@gmail.com>
Co-authored-by: BlackDex <black.dex@gmail.com>

Cargo.lock

@@ -3520,6 +3520,20 @@ dependencies = [
  "web-time",
 ]
 
+[[package]]
+name = "opendal-http-transport-reqwest"
+version = "0.59.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "401999057db611e592f883fcf2cbd6754ff37af587deaadd07b8c1398b2b6b06"
+dependencies = [
+ "bytes",
+ "futures",
+ "http 1.5.0",
+ "http-body 1.1.0",
+ "opendal-core",
+ "reqwest",
+]
+
 [[package]]
 name = "opendal-service-fs"
 version = "0.59.1"
@@ -5989,6 +6003,7 @@ dependencies = [
  "num-derive",
  "num-traits",
  "opendal",
+ "opendal-http-transport-reqwest",
  "openidconnect",
  "openssl",
  "pastey 0.2.3",