Daemon is now capable of providing version information through the
`--version` cli option.

All the relevant env variables are now prefixed with GKFS instead of
ADAFS

get rid of adafs name from folder names

We now use getaddrinfo syscall instead of parsing /etc/hosts in order to
resolve hostnames

A new cli parameter `--listen`,`-l` allow to specify binding address/interface

RPC port can now be configured at runtime through `--bind-port` command line argument.

For some comunication layers an out of band communication is required for putting in place the specific protocol handshake.

In those case a shared lookup file could be used to distribute deamon's endpoints information to all the clients.

This file need to resides on a shared filesystem and can be specified using the new CLI parameter `--lookup-file`.

CHECK_ACCESS didn't make any sense since internally we don't support uid/gid

DO_LOOKUP were not used at all

gid and uid metadata fields have never been used and can be removed
safely

The access RPC have been removed. The POSIX access functionality now is implemented through the stat RPC. This makes code easier to maintain and modify.

There would be a little performance degradation on the POSIX access
function because we are now retrieving also the metadata
associated to the file.

This change makes a lot easier to add symlink support