Move policy-server to a sub-crate. This makes possible to handle a rust
project which delivers multiple binaries.

Signed-off-by: Flavio Castelli <[email protected]>

Prepare the repo layout to accomodate for the policy-optimizer binary

Signed-off-by: Flavio Castelli <[email protected]>

Now that we moved to a cargo workspace, the lock file is handled at the
root of the workspace. Meaning `crates/policy-server/Cargo.lock` is
no longer used.

Signed-off-by: Flavio Castelli <[email protected]>

Update the local Dockerfile to add the policy-optimizer binary to it.

Signed-off-by: Flavio Castelli <[email protected]>

Declare the shared dependencies of policy-server and policy-optimizer in
a single place.

Signed-off-by: Flavio Castelli <[email protected]>

Add the initial implementation of policy-optimizer. Right now the code
use the Lease objects to ensure only one policy-optimizer process can
write to the shared storage.

Right now no real work is done, the code just enters a long sleep. This
is enough to test if this approach works as we expect.

Signed-off-by: Flavio Castelli <[email protected]>