logger: Reimplement date formatting
logger: Reimplement date formatting

Quite easy since we just need to support our own format.

cozy-labs/cozy-desktop,cozy-labs/cozy-desktop,cozy-labs/cozy-desktop,nono/cozy-desktop,nono/cozy-desktop,nono/cozy-desktop,cozy-labs/cozy-desktop,nono/cozy-desktop