feat: add support for themes

[noahgorstein]

This PR adds the following:

• a command line flag (-t/--theme) allowing a user to specify a theme. Themes currently supported are dracula, nord, monokai, monokailight, autumn and default.

Demo of using nord theme:

• The ability for a user to specify a configuration file for jqp. If a configuration option is specified in both the configuration file and via a command line flag, the command line flag takes precedence. By default, jqp will attempt to search for a configuration file named .jqp.yaml in a user's home directory. A path to the configuration file can also be provided via the --config flag.
  • The only really useful thing right now is to put a theme in the config file but this should be helpful later if and when we introduce more configuration options.
• Fixes a bug where the syntax highlighting (being done by Chroma) was highlighting by default for terminals with 16 color ANSI support. We now detect what kind of color support the user's terminal has and highlight based on that.