Rename project to apocapoc-api

Update module name and all imports from habit-tracker-api to apocapoc-api.
This reflects the project's new branding as part of the apocapoc ecosystem
(apocapoc-api, apocapoc-web, apocapoc-android).

.env.example

@@ -1,5 +1,5 @@
 DB_TYPE=sqlite
-DB_PATH=./data/habits.db
+DB_PATH=./data/apocapoc.db
 
 PORT=8080
 HOST=0.0.0.0