Daemon: introduce storage backend

See merge request zdvresearch_bsc/adafs!60

Acknowledge the main thread that the IO operation had terminate before
to actually close the file.

This is a "dirty" fix that waits to be refactored.

WARNING: Error on close will not be reported to the client that issued the IO
operation.

Data operation has been grouped under a ChunkStorage class
that will manage all the data backend operations.

The instance of this object is stored into the ADAFS_DATA sigleton.

Use CMake imported target for Boost components

See merge request zdvresearch_bsc/adafs!68

Introduce MetadataDB class

See merge request zdvresearch_bsc/adafs!67

Preload includes cleanup

See merge request zdvresearch_bsc/adafs!64

docker: changed dependencies build path

See merge request zdvresearch_bsc/adafs!66

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.

move file map into context

See merge request zdvresearch_bsc/adafs!65

Multiple logs handling

See merge request zdvresearch_bsc/adafs!59

Use relative paths

See merge request zdvresearch_bsc/adafs!58

Signed-off-by: Marc Vef <vef@uni-mainz.de>

During daemon setup, multiple spdloggers are configured.

Using spdlog::get("<LOGNAME>") is possible to retrieve those and use
them in other part of the code.

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.

Fix update size

See merge request zdvresearch_bsc/adafs!57

Metadata::serialize() was appending result instead of ovewriting it.

The new approach is to make serialize function return a new constructed
string instead of accepting a string reference to fill.

bump RocksDB version to `5.12.4`

See merge request zdvresearch_bsc/adafs!56