Add stylized 'blurry' and plugin table to CLI output

[johnfraney]

This PR adds a stylized "blurry" at the top of the CLI output for recognition, adds plugins in a table rather than printing lists, and updates the line about gathered tasks to mention Markdown files specifically. I'll likely put up a follow-up PR to add an image processing progress bar, which will be helpful because image processing happens in the background.

Before:

Markdown plugins:
['container', 'punctuation', 'python_code', 'python_code_in_list']
HTML plugins:
['minify_html']
Jinja filter plugins:
[]
Gathered 21 tasks
Built site in 0.102329 seconds

After:

.  .             
|-.| . ..-..-.. .
`-''-'-''  '  '-|
              `-'
┏━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ Markdown Plugins    ┃ HTML Plugins ┃ Jinja Plugins ┃
┡━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ container           │ minify_html  │               │
│ punctuation         │              │               │
│ python_code         │              │               │
│ python_code_in_list │              │               │
└─────────────────────┴──────────────┴───────────────┘
Blurring 17 Markdown files from: content
Built site in 0.160482 seconds