meson_options: implement disable-auth; delete pam

Implemented the disable-auth option.
This patch also removed the pam option which never worked.

Tested:
With disable-auth,

```
~# wget -qO- http://localhost/redfish/v1/Systems/
{
  "@odata.id": "/redfish/v1/Systems",
  "@odata.type": "#ComputerSystemCollection.ComputerSystemCollection",
  "Members": [
    {
      "@odata.id": "/redfish/v1/Systems/system"
    }
  ],
  "Members@odata.count": 1,
  "Name": "Computer System Collection"
}
```

Without disable-auth,

```
~# wget -qO- http://localhost/redfish/
{
  "v1": "/redfish/v1/"
}
~# wget -qO- http://localhost/redfish/v1/Systems/system
wget: server returned error: HTTP/1.1 401 Unauthorized
```

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I88e4e6fa6ed71096bc866b42b9af283645a65988
diff --git a/include/authorization.hpp b/include/authorization.hpp
index 40a6119..202628c 100644
--- a/include/authorization.hpp
+++ b/include/authorization.hpp
@@ -223,7 +223,8 @@
 #endif
 
 // checks if request can be forwarded without authentication
-static bool isOnAllowlist(std::string_view url, boost::beast::http::verb method)
+[[maybe_unused]] static bool isOnAllowlist(std::string_view url,
+                                           boost::beast::http::verb method)
 {
     if (boost::beast::http::verb::get == method)
     {
@@ -255,12 +256,13 @@
     return false;
 }
 
-static std::shared_ptr<persistent_data::UserSession> authenticate(
-    boost::asio::ip::address& ipAddress [[maybe_unused]],
-    Response& res [[maybe_unused]], boost::beast::http::verb method,
-    const boost::beast::http::header<true>& reqHeader,
-    [[maybe_unused]] const std::shared_ptr<persistent_data::UserSession>&
-        session)
+[[maybe_unused]] static std::shared_ptr<persistent_data::UserSession>
+    authenticate(
+        boost::asio::ip::address& ipAddress [[maybe_unused]],
+        Response& res [[maybe_unused]], boost::beast::http::verb method,
+        const boost::beast::http::header<true>& reqHeader,
+        [[maybe_unused]] const std::shared_ptr<persistent_data::UserSession>&
+            session)
 {
     const persistent_data::AuthConfigMethods& authMethodsConfig =
         persistent_data::SessionStore::getInstance().getAuthMethodsConfig();