Add vConnect to CConnman::Options

Summary:
Split the "-connect" argument parsing out of CConnman and put it into
AppInitMain().

Backport core PR10596

Test Plan:

make check

Reviewers: #bitcoin_abc, schancel

Reviewed By: #bitcoin_abc, schancel

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1775