Add account parameter to show 'dead' meters

[shahardo]

• In Astral there're several meters with no activity, and they 'lay above' the active meters, so when clicking on the point one sees no electricity data.
• In Eilat there are light-pole meters that have no activity, but they should remain visible.

[shahardo]

• [x] Add a field in the account node to show/hide dead meters
• [x] Remove 'has_electricity' field from meter's API result
• [x] Filter meters API call for 'has electricity' according to meter flag

[shahardo]

Done