Downsampling parameters on "Load Data" do not update the display

[mbsherma]

n_t and n_f don't update the dynamic spectra on the "Load Data" screen; they are also not set to the most ideal values for viewing.

[mbsherma]

Resolved in commit https://github.com/dsa110/dsa110-pol/commit/8b524709ed3fb8aa7ca5070adbdb2d10e91a0b2b ; the Load Data screen has been simplified with the following changes:

• the data will now be loaded at the highest resolution, regardless of nt and nf values; nt and nf now adjust the resolution internally for plotting and analysis, the same way as on the dedispersion screen.
• the ibox, left buffer and right buffer sliders were removed and default to the Heimdall ibox value, 0, and 0 respectively. They can be adjusted on the Filter Screen where they are relevant. The defaultibox value is now displayed on the "FRB Parameters" slide
• the nt, nf, an log2(window) parameters have been linked to the corresponding sliders on other screens, so that changing the downsampling parameters and plotting window range will now do so globally.

Below is a screenshot of the simplified screen layout: