Write a file `uuid` in server's data directory that contains random UUID, generated at startup if file does not exist.

It will be used for several purposes:
- to anonymously identify server in Sentry (currently Sentry is unusable);
- (possible future usage) to identify server in ensemble.

@tavplubix comments?
#include <Interpreters/Session.h>
#include <Access/AccessControlManager.h>
#include <Storages/StorageReplicatedMergeTree.h>
#include <Storages/System/attachSystemTables.h>
#include <AggregateFunctions/registerAggregateFunctions.h>
#include <Functions/registerFunctions.h>
#include <TableFunctions/registerTableFunctions.h>
#include <Formats/registerFormats.h>
#include <Storages/registerStorages.h>
#include <DataStreams/ConnectionCollector.h>
#include <Dictionaries/registerDictionaries.h>
#include <Disks/registerDisks.h>
#include <Common/Config/ConfigReloader.h>
#include <Server/HTTPHandlerFactory.h>
#include "MetricsTransmitter.h"
#include <Common/StatusFile.h>
#include <Server/TCPHandlerFactory.h>
#include <Common/SensitiveDataMasker.h>
#include <Common/ThreadFuzzer.h>
#include <Common/getHashOfLoadedBinary.h>
#include <Common/Elf.h>
#include <Server/MySQLHandlerFactory.h>
#include <Server/PostgreSQLHandlerFactory.h>
#include <Server/ProtocolServerAdapter.h>
#include <Server/HTTP/HTTPServer.h>
#include <filesystem>
#if !defined(ARCADIA_BUILD)
#   include "config_core.h"
#   include "Common/config_version.h"
#   if USE_OPENCL