feat(auth): add OIDC-only member authentication (#686)

* feat(auth): add OIDC member authentication

* docs(auth): document OIDC member login

* fix(auth): address OAuth review feedback

* refactor(auth): move OAuth flow into member provider

server/pkg/types/api.go

@@ -1,6 +1,9 @@
 package types
 
+import "net/http"
+
 type ApiManager interface {
 	Route(r Router)
 	AddRouter(path string, router func(Router))
+	IsAuthenticated(r *http.Request) bool
 }

server/pkg/types/member.go

@@ -9,7 +9,8 @@ var (
 )
 
 type MemberProfile struct {
-	Name string `json:"name"`
+	Name   string `json:"name"`
+	Avatar string `json:"avatar"`
 
 	// permissions
 	IsAdmin               bool `json:"is_admin"                 mapstructure:"is_admin"`