add .env.example files

annotation-preprocessing/.env.example

@@ -0,0 +1,8 @@
+DB_HOST=localhost
+DB_USER=someuser
+DB_PASSWORD=somepassword
+DB_NAME=somedatabase
+
+IMG_SIZE=75
+ROOT_IN=in
+

data-preprocessing/.env.example

@@ -0,0 +1,3 @@
+DATA_FILE=data.json
+OUT_FILE=metadata.csv
+

models/.env.example

@@ -3,5 +3,3 @@
 # the variables declared in .env are loaded in train.py automatically
 # hydra allows you to reference variables in .yaml configs with special syntax: ${oc.env:MY_VAR}
 
-MY_VAR="/home/user/my/system/path"
-MY_KEY="asdgjhawi8y23ihsghsueity23ihwd"