Visualize a type value as a string

[jameskerr]

This is a case where we are using a "type" as a "value". That means we need to visually represent a "type" in a cell in the viewer. I looked at what zq does for this and tried to copy.

{
    _path: "ssl",
    typeof: ({_path:string,ts:time,uid:bstring,id:{orig_h:ip,orig_p:port=(uint16),resp_h:ip,resp_p:port},version:bstring,cipher:bstring,curve:bstring,server_name:bstring,resumed:bool,last_alert:bstring,next_protocol:bstring,established:bool,cert_chain_fuids:[bstring],client_cert_chain_fuids:[bstring],subject:bstring,issuer:bstring,client_subject:bstring,client_issuer:bstring,validation_status:bstring,ja3:bstring,ja3s:bstring})
}

To implement this, I've added a toString() method to every zed type. I also created an abstract BasePrimitive<T> class to represent the expected interface of a primitive type, and to implement 2 methods that are the same for all primitives (toString() and serialize()).

fixes #1725

[mason-fish]

lgtm, nice that extending instead of implementing the primitive ended up cleaning a lot of repeated code

[mason-fish]

👍