EF fixes

[brockallen]

This PR fixes two EF issues:

• Client Store query has been reverted to the v5.x style, which makes multiple round trips to avoid the matrix multiplication when an inner join is used for the various child tables. Customers were experiencing worse performance with the inner join.

Fixes: #694

• Quickstart Admin Pages for Client Creation: They were missing storing the client secret and the AllowOfflineAccess settings.

[hugoqribeiro]

Have you tried AsSplitQuery? It works fine. I've confirmed that in our override of the client store.

[brockallen]

Have you tried AsSplitQuery? It works fine. I've confirmed that in our override of the client store.

Doesn't that have the same effect as the way the code is written now?

[brockallen]

Doesn't that have the same effect as the way the code is written now?

I just looked at the difference (at least on SqlServer). The AsSplitQuery doesn't reset the connection across the child tables queries, whereas the older approach does. I guess that'd end up being more efficient?