HS20: Support credentials with multiple home OIs

HS20: Support credentials with multiple home OIs

Until now Hotspot 2.0 credentials were only supporting one home OI (with
roaming_consortium option) and one required home OI (with
required_roaming_consortium option). To improve the compliance with
Passpoint specification, add the support for multiple home and required
OIs.

The lists of OIs are provided using two new configuration options
home_ois and required_home_ois that expect a list of OIs formatted as
the roaming_consortiums list. It allows to keep the old options to avoid
breaking currently running configurations and better fits the vocabulary
used in the spec.

The OI match algorithm is updated to implement the behavior described in
Passpoint specification v3.2 section 9.1.2 (Home OIs nodes description
PerProviderSubscription/<X+>/HomeSP/HomeOIList/<X+>).

Signed-off-by: Damien Dejean <damiendejean@chromium.org>