Ramon Nou authored Nov 05, 2020 and Ramon Nou committed Dec 07, 2020

Added dirents_extended to get directory entries of a dir and a single server, added find proposal for io500, added tests

Reformatted code w.r.t. unifying code styles as of the official
CPPCoreGuidelines by Stroustrup and Sutter

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

Implemented all the logic to handle truncate operation.

Test: added truncate test

exposes a new  DB function that allows to retrieve all the
first-level entries of a specific directory.

The metadataDB class was using integer to return errors.
New exceptions classes has been introduced in order to be used as error
propagation method.

In this commit the MetadataDB::get function has been modified in order
to make use of exceptions.