Restructuring code w.r.t. configurations and definitions:
- #defines have been mostly removed from configurations
- a dedicated config file has been added for configurations with constexpr
- past configure file is now only a cmake wrapper
- wrapping global functions into namespaces

Removed all adafs and ifs occurrences. Now called gkfs

`adafs_preload_client` -> `gkfs_intercept`

add support for path resolution, this will be used to get canonical path.

More info at `man path_resolution`

Tokenizer components of boost suite is an header-only library that must
be explicitely imported through the Boost::boost imported target

margo, argobots and mercury have been updated. The abt-snoozer dep
required by margo it is not needed anymore.

RocksDB has been also updated to the lastest release

loggers can be now configured at execution time, by using environment
variables for both server and client.

Server:
 - ADAFS_LOG_LEVEL
 - ADAFS_DAEMON_LOG_PATH

Client:
 - ADAFS_LOG_LEVEL
 - ADAFS_PRELOAD_LOG_PATH

Avoid the usage of a custom cmake "find-module" for mercury.
Instead use the official exported target

In the glibc both readdir and closedir functions marks the @dirp parameter
with a non-null attribute.
If we use a compiler optimization level grater then 1,
the `dirp == nullptr` expression is evaluated to false
at compilation time and the relative if blocks is cutted out
of the final binary.

In order to avoid this bheaviour, we implement a functions and then set
that as weak alias of the real glibc function call.

In order to support directories functionalities
opendir,readdir,closedir,etc.. the OpenDir class has been introduced.
This is a new specialization of the OpenFile class so that OpenDir
object can be stored in the open_file_map along with regular file.

Paths are now made relative to the mountdir at client side.

The new relativize_path fucntion in the PreloadContext is used to check
if a path is relative to the pseudo-mount directory and to make it
relative

The new PreloadContext class is used as singleton to store the general context
information of the interception library.

The plan is to move global accessed variables into this sigleton.

At the moment just the logger object has been moved into it.

Previously, clients would look for the daemon by name which was not robust.
If the daemon was started with valgrind for example, clients would not find
the daemon.

Similar to other applications a daemon now creates a pid file with
information about its pid and its started mountdir.

Proper errorhandling on server and client side was added.

Multiple daemons per node are explicitly not allowed for now!

The calculus (on clients) about the last chunk involved into a
write/read operation was bugged.

A new blocks_calc_util library has been introduced in order to make
easier to perform this kind of calculus.

Use cmake in order to properly check and use both the Boost library and
the pthread one.