Remember last valid SLURM in case of syntax error with newer SLURM(s).

Remember last valid SLURM in case of syntax error with newer SLURM(s).

-Remove 'comment' member from slurm structs, there's no need to store its value.
-Rename 'slurm/slurm_db.*' to 'slurm/db_slurm.*'.
-Allocate SLURM data, so that the last valid SLURM can be used if needed; so, now the SLURM lives on the heap and is 'remembered' as part of the VRPs state. Also remember the date and time when the last valid SLURM was loaded.
-Move 'slurm_bgpsec' and 'slurm_prefix' structs, and SLURM data flags to 'db_slurm.h'.
-Update 'slurm_parser' to return a specific error in case of a syntax error, so that further actions can be taken (ignore slurm, use last valid version, or store as the last valid version).
-In case a previous valid version of SLURM is utilized, log a WARNING indicating that such action is being taken, and log SLURM content at INFO level.
-Fix bug at common function 'process_file', there was an issue before releasing temporal pointers.