Fediverse-based authentication (#1846)

* Able to authenticate user against IndieAuth. For #1273

* WIP server indieauth endpoint. For https://github.com/owncast/owncast/issues/1272

* Add migration to remove access tokens from user

* Add authenticated bool to user for display purposes

* Add indieauth modal and auth flair to display names. For #1273

* Validate URLs and display errors

* Renames, cleanups

* Handle relative auth endpoint paths. Add error handling for missing redirects.

* Disallow using display names in use by registered users. Closes #1810

* Verify code verifier via code challenge on callback

* Use relative path to authorization_endpoint

* Post-rebase fixes

* Use a timestamp instead of a bool for authenticated

* Propertly handle and display error in modal

* Use auth'ed timestamp to derive authenticated flag to display in chat

* Fediverse chat auth via OTP

* Increase validity time just in case

* Add fediverse auth into auth modal

* Text, validation, cleanup updates for fedi auth

* Fix typo

* Remove unused images

* Remove unused file

* Add chat display name to auth modal text

activitypub/apmodels/webfinger.go

@@ -11,6 +11,11 @@ type WebfingerResponse struct {
 	Links   []Link   `json:"links"`
 }
 
+// WebfingerProfileRequestResponse represents a Webfinger profile request response.
+type WebfingerProfileRequestResponse struct {
+	Self string
+}
+
 // Link represents a Webfinger response Link entity.
 type Link struct {
 	Rel  string `json:"rel"`
@@ -41,3 +46,18 @@ func MakeWebfingerResponse(account string, inbox string, host string) WebfingerR
 		},
 	}
 }
+
+// MakeWebFingerRequestResponseFromData converts WebFinger data to an easier
+// to use model.
+func MakeWebFingerRequestResponseFromData(data []map[string]interface{}) WebfingerProfileRequestResponse {
+	response := WebfingerProfileRequestResponse{}
+	for _, link := range data {
+		if link["rel"] == "self" {
+			return WebfingerProfileRequestResponse{
+				Self: link["href"].(string),
+			}
+		}
+	}
+
+	return response
+}