Fix concurrent writing and reading on workers boot

[wapmorgan]

Set a shared lock on a file in Memoty::loadData() to prevent reading an empty file while writing it in concurrent worker/process

Q	A
Bugfix?	✔️
Breaks BC?	❌
New feature?	❌
Issues	Can get an empty file when file_put_contents in \Spiral\Boot\Memory::saveData=>\Spiral\Files\Files::write created, but not completed write to file
Docs PR	spiral/docs

Got this problem when 2 jobs consumers concurrently started writing/reading runtime/cache/cycle.php file. First consumer writing schema to the file, second consumers find out that files exists and read it, but it still was empty = so read empty schema.

[wapmorgan]

Also another option is to remove LOCK_NB and remain only LOCK_SH to force current thread to wait until it will be able to make shared lock.
In current MR's code current thread will build schema again and write it to file again.

[roxblnfk]

@wapmorgan hi, the first commit was OK. Could you revert the last change?