[WIP] Feature/add csv renderer extension

[akinsho]

Initial implementation of a csv previewer the idea is similar functionality (but more basic) as vscode excel preview i.e. a csv in a tabular format in an overlay -> thats the end goal, fancier functionality can come later.

• N.B - decided not to user virtualized for now as its a fairly complex solution and was proving a blocker for the initial implementation

[akinsho]

@CrossR if you get a chance would love some feedback on this since you also use csv a bit, I'm aiming for something V. minimal for now aka just renders a csv in a more readable tabular format.

There's some outstanding stuff I need to add like a flag to hide it behind, and it theres loads of room to make it more advanced in the future.

there are 3 commands experimental.csv.preview.toggle, experimental.csv.preview.next and experimental.csv.preview.previous (I added pagination with large csvs in mind) the aim is a user can specify how many rows should render and then paginate through the rest