docs(nuget): include package readmes

Add package-specific NuGet readmes for both HrynCo DAL packages.

Ref: hrynco/hrynco-ef#18

HrynCo.DAL.Abstract/HrynCo.DAL.Abstract.csproj

@@ -6,6 +6,7 @@
     <Nullable>enable</Nullable>
     <RootNamespace>HrynCo.DAL.Abstract</RootNamespace>
     <PackageId>HrynCo.DAL.Abstract</PackageId>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>HrynCo</Authors>
     <Description>Abstract DAL contracts for HrynCo applications: entities, repository and unit-of-work interfaces.</Description>
     <PackageTags>hrynco dal abstract entity repository unitofwork</PackageTags>
@@ -13,5 +14,9 @@
     <RepositoryUrl>https://gitea.hrynco.com/hrynco/hrynco-ef.git</RepositoryUrl>
   </PropertyGroup>
 
+  <ItemGroup>
+    <None Include="README.md" Pack="true" PackagePath="/" />
+  </ItemGroup>
+
 </Project>