ice.4: Update man page

This is a combination of imported information from the out-of-tree
driver's documentation, as well as some all new information:

• Add previously undocumented loader tunables and expand the descriptions

for all of them

• Add references to the iavf and irdma man pages
• Add some documentation for the DDP package (ice_ddp)
• Remove mentions of the ports/packages for the utilities since those are

no longer supported, and update the names of the utilities to match the
names used on the Intel Download Center

• Add information on RDMA and RDMA mirroring sections
• Document QoS capability

And more!

Signed-off-by: Eric Joyner <erj@FreeBSD.org>

Reviewed by: ziaee@
Pull Request: https://github.com/freebsd/freebsd-src/pull/1622
Closes: https://github.com/freebsd/freebsd-src/pull/1622