Feature/spinner time

[Vanderhoof]

Add running time to extensions stdout, example:

$ foliant make site
Parsing config... Done in 0.001s
Applying preprocessor includes... Done in 0.02s
Applying preprocessor argdown... Done in 4.919s
Applying preprocessor graphviz... Done in 0.006s
Applying preprocessor mkdocs... Done in 0.113s
Applying preprocessor _unescape... Done in 0.003s
Making site with MkDocs... Done in 0.345s
────────────────────
Result: my_project.mkdocs