[web/views/staticcontrollers] Make ConcatFilesHandler write to a tempfile In order to be more resistant to errors such as ENOSPC, and against different threads accessing the same static data, we: - concatenate data files to a temporary file, and rename it once we're done - delete the tempfile in case of errors - protect the creation of the cache_concat file with a lock Closes #3005547

[MESSAGES CONTROL]
disable-msg = C0301

[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name

[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$

[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception