Lazy initialization of queue inside dpcpp_default policy

[adamfidel]

There are a few potential issues with oneDPL's global sycl::queue, including:

• Requirement that a SYCL device is available whenever oneDPL is included as mentioned in #1060
• Static initialization order fiasco with regard to queues being defined in other translation units

To address the issue, this PR lazily initializes the sycl::queue inside the dpcpp_default execution policy on first use.

[rarutyun]

Just to state it explicitly. Those are not all comments that I have. I am thinking about Sergey's comment about virtuality and also about additional things for copy/move semantics

[akukanov]

After merging #1652, this patch is outdated.