Reworked noise NoiseAdjustGadget

This is a rework of the NoiseAdjustGadget. This Gadget is central to many recon chains and it is important that it works well, please review carefully. 

Major changes include:
1. Elimination of many redundant paths through the code
2. Elimination of various header field queries that were never used
3. Elimination of references to surface coil correction scans
4. Elimination of reliance of noise_dwell_time_us_preset (the interpretation of this parameter if now that if it is set, it replaces any set dwell_time for noise). The Gadget otherwise assumes that data is correctly labels with dwell times. 
5. Refactoring of code to generate file name
6. The Gadget now stores the covariance instead of the prewhitener
7. The XML header of the noise adjust is stored with the covariance to enable parsing of the coil labels. 
8. Coil labels are compared between stored covariance and the measurement. The Gadget will fail if they are not the same.