[SPDK] [Release] 20.10: NVMe-oF multipath, NVMe ZNS, iSCSI login redirection

On behalf of the SPDK community I'm pleased to announce the release of SPDK 20.10!

This release contains the following new features:

- NVMe-oF Multipath: The NVMe-oF target now supports Asymmetric Namespace Access (ANA) reporting to provide multipath to NVMe-oF initiator.
- NVMe ZNS: Zoned Namespace Command Set support has been added to NVMe driver. See https://spdk.io/doc/nvme__zns_8h.html for details.
- iSCSI Redirection: The iSCSI target supports iSCSI login redirection feature to achieve fault tolerance and load balancing particularly in scale out iSCSI target system.
- Interrupt mode: Added support for interrupt mode. It allows modules or libraries to selectively register file descriptors that the spdk_thread can wait on. This feature is considered experimental and enabled in a very small subset of SPDK libraries and modules.
- Scheduler and governor: Added thread scheduler and CPU frequency governor frameworks used to rebalance load among CPU cores. This feature is considered experimental.
- Legacy configuration removed: SPDK applications and bdev modules no longer support legacy INI style configuration. Only JSON-RPC configuration is supported, see https://spdk.io/doc/jsonrpc.html for details.


The full changelog for this release is available at:
https://github.com/spdk/spdk/releases/tag/v20.10

This release contains 805 commits from 43 authors with over 47k lines of code changed.

We'd especially like to recognize all of our first time contributors:

	Jimbo Lu
	Krzysztof Karas
	Niklas Cassel
	Pawel Piatek
	Rafal Stefanowski
	Vasuki Manikarnike
	Wang Shilong


Thanks to everyone for your contributions, participation, and effort!

Thanks,
Tomek