Remove conversions, add percentages and fix typos in Meltano Models for Facebook Ads

This MR:

1. Removes all the actions_conversions aggregates (as their base sql attribute is removed by dbt-tap-facebook#6 (closed))
2. Uses the renamed result_rate_from_clicks instead of results_per_click
3. Converts Result Rate from Click to a proper percentage --> multiply by 100 and add a % to the Metric's label to hint that this is a percentage
4. Adds a % to the CTR's label to hint that this is a percentage
5. Adds an m to all words (e.g. Ipressions --> Impressions)

Closes #5 (closed)