Caching previous downloads

Rationale

This will allow a search or find command to be possible from previously downloaded videos.

[x] It shall be stored in a .video-manager_history file at $HOME or otherwise defined in the config file
[x] The file format shall be similar to how files are read from the -f flag from the get command, with each line being a new entry
[ ] ~Each entry should contain information for the video name and download url~
[x] The get command should also write to this file
[x] The get command should also search the cache file if it encounters a non-url
[x] A cache command should also be developed to edit the file