Fix EOSdash startup (docker)

* Docker: Copy the same directory structure (src/) to support the
   lifespan startup of EOSdash.
   Use EOS_SERVER_EOSDASH_SESSKEY environment variable to provide
   EOSdash with session key.

.dockerignore

@@ -1,8 +1,8 @@
 .git/
 .github/
-eos-data/
-mariadb-data/
-test_data/
+**/__pycache__/
+**/*.pyc
+**/*.egg-info/
 .dockerignore
 .env
 .gitignore
@@ -12,4 +12,4 @@ LICENSE
 Makefile
 NOTICE
 README.md
-.venv
+.venv/