feat: initial solution with HrynCo.DAL.Abstract and HrynCo.DAL.EF

- HrynCo.DAL.Abstract: IEntity<TId>, Entity base classes, ITransaction, IUnitOfWork
- HrynCo.DAL.EF: EfRepository<TDbContext,TEntity>, EfUnitOfWork<TDbContext>, EfTransactionAdapter
- Directory.Packages.props with centralized EF Core 9.0.5 versions
- TeamCity pipeline YAMLs for general-checks and publish

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.teamcity/pipelines/general-checks.yaml

@@ -0,0 +1,13 @@
+jobs:
+  general-checks:
+    name: general-checks
+    runs-on:
+      self-hosted:
+        - teamcity.agent.name: ItemTrackerDotNet10
+    steps:
+      - type: script
+        script-content: dotnet restore hrynco-ef.slnx
+      - type: script
+        script-content: dotnet build hrynco-ef.slnx -c Release --no-restore
+      - type: script
+        script-content: dotnet test hrynco-ef.slnx --no-build -c Release