Growth & Engagement: Change from `%` increases to numbers

# Problem

* The `+2% last week` type of increments are very difficult because the larger Joystream becomes, the harder it is to move these numbers significantly, especially on a week long timescale.
* I kind of feel from a marketing/selling point perspective that rounded percentages don't do well. For example the number of profiles/memberships is stated as `+1% Last week` and this is a very boring way of putting it. If it were put in numbers instead, it would be a much bigger selling point, in this example if it were changed it would read as `596 in the last week`
* Likewise for videos--`+2% Last week` would read a lot better as being `13,205 in the last week`. That is a lot of videos and a lot more of an interesting story to tell "outsiders" of the project than just a simple `2%` figure

# Solution
* Change the `%` reference to stated numbers