server: refactor + add type hinting

- Added type hinting (for now, 3.5-compatible)
- Split `db` namespace into `db` module and `model` namespace
- Changed elastic search to be created lazily for each operation
- Changed to class based approach in entity serialization to allow
  stronger typing
- Removed `required` argument from `context.get_*` family of functions;
  now it's implied if `default` argument is omitted
- Changed `unalias_dict` implementation to use less magic inputs

1 files changed, 3 insertions, 2 deletions

diff --git a/server/szurubooru/config.py b/server/szurubooru/config.py
index e569311..567b457 100644
--- a/server/szurubooru/config.py
+++ b/server/szurubooru/config.py
@@ -1,8 +1,9 @@
+from typing import Dict
 import os
 import yaml
 
 
-def merge(left, right):
+def merge(left: Dict, right: Dict) -> Dict:
     for key in right:
         if key in left:
             if isinstance(left[key], dict) and isinstance(right[key], dict):
@@ -14,7 +15,7 @@ def merge(left, right):
     return left
 
 
-def read_config():
+def read_config() -> Dict:
     with open('../config.yaml.dist') as handle:
         ret = yaml.load(handle.read())
         if os.path.exists('../config.yaml'):