refactored server-side code

[pranavsuku-db]

Moved Codec.scala, DeletionVectorDescriptor.scala, DeltaAction.scala into actions package in common. Moved CloudFileSigner.scala and DeltaAction.scala into common. This meant changing the imports in some other files.

This PR is purely a refactor and does not change any core logic. Does not require any additional testing since it is just a refactor

[pranavsuku-db]

The tests that are failing are connection timeouts and these tests have been flaky. Not related to to this work

[pranavsuku-db]

@linzhou-db I will probably address this in the JSON predicate hints PR where I add more files related to kernel, but do you have any ideas for what I should name the current package kernelsharedtable to? It is not consistent with the rest of the package names and feels a bit clunky. The issue is I cannot rename it to kernel.internal similar to how standalone.internal is named since that will conflict with the actual import from kernel.internal. One idea is we rename standalone.internal to sharing.standalone.internal and do the same for the new sharing.kernel.internal

[linzhou-db]

@linzhou-db I will probably address this in the JSON predicate hints PR where I add more files related to kernel, but do you have any ideas for what I should name the current package kernelsharedtable to? It is not consistent with the rest of the package names and feels a bit clunky. The issue is I cannot rename it to kernel.internal similar to how standalone.internal is named since that will conflict with the actual import from kernel.internal. One idea is we rename standalone.internal to sharing.standalone.internal and do the same for the new sharing.kernel.internal

sharing.standalone.internal and sharing.kernel.internal sounds good to me.