Add Visibility Monitor Component

[maxscheel]

• Show in vis data mode
• 'Visibility Monitor' Component
  select i-th antenna, select j-th antenna (perhaps dropdown.)
  only allow j to be selected after i has been selected and j>i

1. Display current magnitude and phase
2. Plot Magnitude[1] in log10() and Phase [rad] vs. time

reuse or share vis data that is requested in imaging component

misc:
mag = Math.sqrt(Math.pow(re,2) + Math.pow(im,2))
phase = Math.atan2(im, re)

nice to have:
set range of time for display last N (e.g. 10-500) magnitude and phases