Help translators do their job better

Addresses #17.

This MR fixes some maintenance-related problems regarding our source strings and adds a plethora of comments that explain requirements, context and the thinking that went behind the source strings, as well as an overview as to where the string "fits in". I believed I added an amount of information that was appropriate, on a case-by-case basis.

My goal was to answer as many questions that a translator may have as possible. I used my past experiences as a point of reference. Many comments may seem redundant, but were copied and pasted under the assumption that a translator may not want to look through other "neighboring" translations in order to better understand the greater picture. I believe that such an approach may reduce the amount translations that are half-completed, as I am assuming that multiple different people will work on a specific language throughout the years and will not have a way to communicate with each other when building on top of each others' work.