Add: formatting options to list command

[dinhtungdu]

In this PR I use WP_CLI\Formatter instead of cli\Table to display the output of list command. This unlocks many display functionalities supported by WP_CLI\Formatter out of the box. See the new help text for the command below.

Fixes #237

  wp safe-redirect-manager list [--field=<field>] [--fields=<field1,field2>] [--format=<format>] [--show_total=<bool>]

  Available fields: 'ID', 'redirect_from', 'redirect_to', 'status_code', 'enable_regex', 'post_status'.

  [--field=<field>]
    Single field to dipslay, should be one of available fields.

  [--fields=<field1,field2>]
    Multiple fields to dipslay, should be a list of available fields.

  [--format=<format>]
    The command output format. Can be table, json, csv, yaml. Default to table.

  [--show_total=<bool>]
    Show total redirects. Default to true.

[jeffpaul]

@TheLastCicada any feedback on review of this PR that addresses your related issue?