Reintroduce dropped v2 dynamic config

Co-authored-by: Baptiste Mayelle <baptiste.mayelle@traefik.io>

docs/content/middlewares/http/contenttype.md

@@ -52,3 +52,16 @@ http:
 [http.middlewares]
   [http.middlewares.autodetect.contentType]
 ```
+
+## Configuration Options
+
+### `autoDetect`
+
+!!! warning
+
+    `autoDetect` option is deprecated and should not be used.
+    Moreover, it is redundant with an empty ContentType middleware declaration.
+
+`autoDetect` specifies whether to let the `Content-Type` header,
+if it has not been set by the backend,
+be automatically set to a value derived from the contents of the response.

docs/content/middlewares/http/headers.md

@@ -314,11 +314,43 @@ The `allowedHosts` option lists fully qualified domain names that are allowed.
 
 The `hostsProxyHeaders` option is a set of header keys that may hold a proxied hostname value for the request.
 
+### `sslRedirect`
+
+!!! warning
+
+    Deprecated in favor of [EntryPoint redirection](../../routing/entrypoints.md#redirection) or the [RedirectScheme middleware](./redirectscheme.md).
+
+The `sslRedirect` only allow HTTPS requests when set to `true`.
+
+### `sslTemporaryRedirect`
+
+!!! warning
+
+    Deprecated in favor of [EntryPoint redirection](../../routing/entrypoints.md#redirection) or the [RedirectScheme middleware](./redirectscheme.md).
+
+Set `sslTemporaryRedirect` to `true` to force an SSL redirection using a 302 (instead of a 301).
+
+### `sslHost`
+
+!!! warning
+
+    Deprecated in favor of the [RedirectRegex middleware](./redirectregex.md).
+
+The `sslHost` option is the host name that is used to redirect HTTP requests to HTTPS.
+
 ### `sslProxyHeaders`
 
 The `sslProxyHeaders` option is set of header keys with associated values that would indicate a valid HTTPS request.
 It can be useful when using other proxies (example: `"X-Forwarded-Proto": "https"`).
 
+### `sslForceHost`
+
+!!! warning
+
+    Deprecated in favor of the [RedirectRegex middleware](./redirectregex.md).
+
+Set `sslForceHost` to `true` and set `sslHost` to force requests to use `SSLHost` regardless of whether they already use SSL.
+
 ### `stsSeconds`
 
 The `stsSeconds` is the max-age of the `Strict-Transport-Security` header.
@@ -370,6 +402,14 @@ The `publicKey` implements HPKP to prevent MITM attacks with forged certificates
 
 The `referrerPolicy` allows sites to control whether browsers forward the `Referer` header to other sites.
 
+### `featurePolicy`
+
+!!! warning
+
+    Deprecated in favor of [`permissionsPolicy`](#permissionsPolicy)
+
+The `featurePolicy` allows sites to control browser features.
+
 ### `permissionsPolicy`
 
 The `permissionsPolicy` allows sites to control browser features.

docs/content/middlewares/http/stripprefix.md

@@ -76,3 +76,72 @@ For instance, `/products` also matches `/products/shoes` and `/products/shirts`.
 
 If your backend is serving assets (e.g., images or JavaScript files), it can use the `X-Forwarded-Prefix` header to properly construct relative URLs.
 Using the previous example, the backend should return `/products/shoes/image.png` (and not `/image.png`, which Traefik would likely not be able to associate with the same backend).
+
+### `forceSlash`
+
+_Optional, Default=true_
+
+!!! warning
+
+    `forceSlash` option is deprecated and should not be used.
+
+The `forceSlash` option ensures the resulting stripped path is not the empty string, by replacing it with `/` when necessary.
+
+??? info "Behavior examples"
+
+    - `forceSlash=true`
+
+    | Path       | Prefix to strip | Result |
+    |------------|-----------------|--------|
+    | `/`        | `/`             | `/`    |
+    | `/foo`     | `/foo`          | `/`    |
+    | `/foo/`    | `/foo`          | `/`    |
+    | `/foo/`    | `/foo/`         | `/`    |
+    | `/bar`     | `/foo`          | `/bar` |
+    | `/foo/bar` | `/foo`          | `/bar` |
+
+    - `forceSlash=false`
+
+    | Path       | Prefix to strip | Result |
+    |------------|-----------------|--------|
+    | `/`        | `/`             | empty  |
+    | `/foo`     | `/foo`          | empty  |
+    | `/foo/`    | `/foo`          | `/`    |
+    | `/foo/`    | `/foo/`         | empty  |
+    | `/bar`     | `/foo`          | `/bar` |
+    | `/foo/bar` | `/foo`          | `/bar` |
+
+```yaml tab="Docker"
+labels:
+  - "traefik.http.middlewares.example.stripprefix.prefixes=/foobar"
+  - "traefik.http.middlewares.example.stripprefix.forceSlash=false"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: example
+spec:
+  stripPrefix:
+    prefixes:
+      - "/foobar"
+    forceSlash: false
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    example:
+      stripPrefix:
+        prefixes:
+          - "/foobar"
+        forceSlash: false
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.example.stripPrefix]
+    prefixes = ["/foobar"]
+    forceSlash = false
+```