BUG/MINOR: quic: Wrong use of now_ms timestamps (newreno algo)

BUG/MINOR: quic: Wrong use of now_ms timestamps (newreno algo)

This patch is similar to the one for cubic algorithm:
    "BUG/MINOR: quic: Wrong use of timestamps with now_ms variable (cubic algo)"

As now_ms may wrap, one must use the ticks API to protect the cubic congestion
control algorithm implementation from side effects due to this.

Furthermore, to make the newreno congestion control algorithm more readable and easy
to maintain, add quic_cc_cubic_rp_cb() new callback for the "in recovery period"
state (QUIC_CC_ST_RP).

Must be backported to 2.7 and 2.6.