this change adds support for a second Victron MPPT charge controller
using a second serial connection.
* Add device configuration for a second victron mppt
* Update VedirectView for second victron mppt
* Update MqttHandleVedirect for second victron mppt
* Update MqttHandleVedirectHass for second victron mppt
* Handle nonexisting victron controllers with optionals
* Add bool-function to Battery and inherited classes, if uart port 2 is
being used
* Introduced a serial port manager. In order to prevent the battery and
the Victron MPPT to use the same hw serial ports, this class keeps
track of the used ports and their owners.
this change utilizes some of the features from library "frozen", which
was included upstream for the grid profile parser. to improve code
maintainability, a couple of std::maps mapping strings to values or the
other way around were introduced in OpenDTU-OnBattery-specific code at
the expense of some flash and computing overhead.
library "frozen" offers constexpr versions of map and string, which
saves initialization code and offers slightly faster lookups. this
brings the binary size down by ~25kB and should provide a small
performance improvement at runtime.
