Liveview dashboard keyboard shortcuts

[RobertJoonas]

Changes

Adds the following keyboard shortcuts to the liveview dashboard spike implementation:

const KEYBOARD_SHORTCUTS = {
  changePeriod: ['r', 'd', 'm', 'y', 'a', 'w', 'f', 't', 'n', 's', 'l'],
  shiftPeriod: ['ArrowLeft', 'ArrowRight'],
  clearFilters: 'Escape'
}

[zoldar]

LGTM. Only a small complaint from credo mix formatter.