Add more meaningful logging for podcast_resources.rb

[yattoz]

This log will be read my everyone, so:

• when submitting an episode into the future, display the link in the log
• remove unclear logging that make the log harder to decipher

[yattoz]

add threading to launch vuepress rebuild while still outputting something in the log file, to show "hey it's doing stuff no worries"

[yattoz]

it's cleaner now, it displays little dots when doing its stuff.