Add CompanyTable model and refactor query handling; update requirements for new dependencies

app/api/companies.py

@@ -0,0 +1,8 @@
+from fastapi.routing import apirouter
+
+router = apirouter()
+
+@router.get("/companies")
+def read_companies():
+    return {"message": "list of companies"}
+

app/api/investors.py

@@ -0,0 +1,8 @@
+from fastapi.routing import apirouter
+
+router = apirouter()
+
+@router.get("/investors")
+def read_investors():
+    return {"message": "list of investors"}
+