adding hidden basic asp.net core backend (#30)

Base functionality:

    DB
    email sending
    user registration & login
    storing new characters and reading them back

Notes:

    Functionality is "hidden" with no links pointing to it.
    Most pages are scaffolded and not reviewed at all :(
    local Dev db setup is pushed to git
    NO local email setup :(

Kemkas.Web/docker-compose.yaml

@@ -0,0 +1,10 @@
+version: "3"
+
+services:
+  db:
+    image: postgres:16.1-alpine3.19
+    ports:
+      - "5432:5432"
+    environment:
+      POSTGRES_USER: "kemkas"
+      POSTGRES_PASSWORD: "kemkas-dev42"