Expand interactive composition methods

[pg8wood]

It can sometimes be cumbersome to open the text editor and add entries using markdown syntax. Create an interactive way to add entries on the command line.

Example flow:

changelog add <-t | --ticket>
Enter the ticket number:
TICKET-1234
Enter the link to the ticket: 
https://blog.patrickgatewood.com

<create entry and emit existing success message>

Maybe let this be done via some flags too:
`changelog add <-t | --ticket>
^ don't forget about argument parser's ability to type check URLs!

After #2, this could be accomplished simply by typing
changelog add -t <hypertext> 1234❗️