OZGrav/meerpipe: PSRDB intergration

Operational version of MeerPipe on the OzStar HPC cluster as of May, 2023. Implements a number of significant upgrades and incremental fixes over the previous version.

• Fully integrated with PSRDB, a backend database which records details of all MeerTIME observations and their subsequent processing through MeerPIPE. PSRDB integration also allows results to be displayed on the MeerTIME Data Portal (pulsars.org.au), along with the download of selected products.
• Full automation, such that new observations are processed as soon as they are transferred onto OzStar from the PTUSE machines.
• Expansion of manual launch options for efficient selection and reprocessing of individual observations.
• Production of reduced data products per the specification of individual projects (PTA / TPA / RelBin, etc.), allowing for the scientific needs of each individual project.
• Complete UHF and L-Band flux and polarisation calibration, thanks to significant input from Simon Johnston, Bettina Posselt & Lucy Oswald.
• Production of diagnostic images, including TOA residuals showing the state of the pulsar's timing.
• Automatic logging of per-observation flux density, S/N and DM values, as well as the fraction of the observation zapped during cleaning.
• Dynamic resource requests for SLURM jobs (RAM & walltime) based on the size of the observation to be processed, allowing for more efficient processing.