Authentication

- add AuthenticationController
- add AuthenticationService
- add getUserByUsername to AccountService
- add findByUsername to AccountRepository
- add SecurityConfiguration
- set up authentication

.editorconfig

@@ -17,6 +17,10 @@ tab_width = 2
 [*.bat]
 end_of_line = crlf
 
+[*.pem]
+max_line_length = 64
+insert_final_newline = false
+
 # noinspection EditorConfigKeyCorrectness
 [*.{kt,kts}]
 ij_kotlin_packages_to_use_import_on_demand = unset