quic: fifo size is u32

quic: fifo size is u32

- Fix cli / config fifo size to only accept u32
  size input.
- Make cli / config fifo-size input type handling
  to be the same as vpp hoststack
- Update external transfer tests to use new
  syntax with different fifo sizes for
  vpp_echo client/server and vpp.

Type: fix

Change-Id: Ia5ddb2b8d3d9908ab502352819eebeec8ac0971d
Signed-off-by: Dave Wallace <[email protected]>