Add PostgreSQL support for mint and wallet (#878)

* Add PostgreSQL support for mint and wallet

* Fixed bug to avoid empty calls `get_proofs_states`

* Fixed SQL bug

* Avoid redudant clone()

* Add more tests for the storage layer

* Minor enhacements

* Add a generic function to execute db operations

This function would log slow operations and log errors

* Provision a postgres db for tests

* Update deps for msrv

* Add postgres to pipeline

* feat: add psgl to example and docker

* feat: db url fmt

---------

Co-authored-by: thesimplekid <tsk@thesimplekid.com>

.github/workflows/ci.yml

@@ -160,6 +160,7 @@ jobs:
         database: 
           [
             SQLITE,
+            POSTGRES
           ]
     steps:
       - name: checkout
@@ -262,6 +263,8 @@ jobs:
           shared-key: "stable"
       - name: Test fake mint
         run: nix develop -i -L .#stable --command just test-pure ${{ matrix.database }}
+      - name: Install Postgres
+        run: bash -x crates/cdk-postgres/start_db_for_test.sh
       - name: Test mint
         run: nix develop -i -L .#stable --command just test