feat(db): add postgresql support

sql/postgres/session_queries.sql

@@ -0,0 +1,43 @@
+-- name: CreateSession :one
+INSERT INTO "sessions" (
+    "uuid",
+    "username",
+    "email",
+    "name",
+    "provider",
+    "totp_pending",
+    "oauth_groups",
+    "expiry",
+    "created_at",
+    "oauth_name",
+    "oauth_sub"
+) VALUES (
+    $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11
+)
+RETURNING *;
+
+-- name: GetSession :one
+SELECT * FROM "sessions"
+WHERE "uuid" = $1;
+
+-- name: DeleteSession :exec
+DELETE FROM "sessions"
+WHERE "uuid" = $1;
+
+-- name: UpdateSession :one
+UPDATE "sessions" SET
+    "username"     = $1,
+    "email"        = $2,
+    "name"         = $3,
+    "provider"     = $4,
+    "totp_pending" = $5,
+    "oauth_groups" = $6,
+    "expiry"       = $7,
+    "oauth_name"   = $8,
+    "oauth_sub"    = $9
+WHERE "uuid" = $10
+RETURNING *;
+
+-- name: DeleteExpiredSessions :exec
+DELETE FROM "sessions"
+WHERE "expiry" < $1;