Plugin enhancements

[AshiqKiron]

1. The blocks in the drag & drop editor have the same color as the background, we should add a different color in the background for better contrast. With a bit of CSS tweaking, we can modernize the look of the editor.
2. Introduce yearly subscription plan along with monthly. This will encourage users to purchase yearly plans, yearly plans will have 20% - 30% discount.
3. Allow users to change email address associated with site URL