Sensitivity calculator upgrades in PI23

Proposed upgrades to the Low and Mid sensitivity calculators during PI23 are

1. Speed up LOW sensitivity calculator
Low sensitivity calculations are currently quite slow because of how the database is queried. Speed up this process. SciOps will contribute code: https://gitlab.com/ska-telescope/ost/ska-ost-senscalc/-/merge_requests/188

2. Add Pulsar Search (PSS) accordion to the Mid sensitivity calculator

The Pulsar Search (PSS) accordion was introduced to the Low calculator in PI21, which allows users to estimate the folded pulse sensitivity for the specified observational setup. In PI23, we want to expand this functionality to the Mid calculator. This is mainly a frontend work since the backend calculations rely on the same functions that were added for Low folded-pulse sensitivity calculation.

The Mid Pulsar Search (PSS) accordion should have the following behaviour:

• As in the case of the Low calculator, the pulsar accordion is enabled only for selected subarray configurations. So, add the following new subarray configurations to the Mid calculator: Mid_inner_r125m_AA*, Mid_inner_r500m_AA*, Mid_inner_r2km_AA*, Mid_inner_r20km_AA*, Mid_inner_r125m_AA4, Mid_inner_r500m_AA4, Mid_inner_r2km_AA4, and Mid_inner_r20km_AA4.
  The pulsar accordion is enabled only if the subarray configuration is set to one of these. These are valid imaging subarrays, so the PSF and WCF lookup tables must be generated.

• The accordion in Mid should have the same input and output fields as in Low.  Use the same defaults as in Low except for
  • Bandwidth = 300 MHz,
  • channel width = 80.64 kHz, and 
  • Central Frequency should be set appropriately depending on the value of the Observing Band field.