NetlistWriter: rename ISOURCE to ISOURCE_PWL

    config_.setDefault<std::string>("file_name", "output_netlist_event");

    file_name_ = config.get<std::string>("file_name");

    // Default source type set to ISOURCE_PULSE

    config_.setDefault<SourceType>("source_type", SourceType::ISOURCE_PULSE);

    // Get the source type, name and the circuit connected to it, as defined in the netlist

    source_type_ = config.get<SourceType>("source_type");

    // Get the source name and the circuit connected to it, as defined in the netlist

    source_name_ = config.get<std::string>("source_name");

    subckt_instance_name_ = config.get<std::string>("subckt_name");

            // ------- ISOURCE-------

            if(source_type_ == SourceType::ISOURCE) {

            if(source_type_ == SourceType::ISOURCE_PWL) {

                // Get pulse and timepoints

                const auto& pulse = pixel_charge.getPulse(); // the pulse containing charges and times

        };

        enum class SourceType {

            ISOURCE,

            ISOURCE_PWL,

            ISOURCE_PULSE,

        };

A new netlist is written for each event, reusing the header, footer, and circuit description from the netlist template specified with the `netlist_template` parameter. For each fired pixel, a source / circuit instance pair is added to the template.

The new source written can be parameterized with the parameter `source_type`. Two different types of sources can be used: `ISOURCE` and `ISOURCE_PULSE`:

The new source written can be parameterized with the parameter `source_type`. Two different types of sources can be used: `ISOURCE_PWL` and `ISOURCE_PULSE`:

* `ISOURCE` allows writing all the temporal current waveform using a PWL (Piecewise Linear). This requires the use of the `[PulseTransfer]` module to get the current waveform. A delay can also be added using `t_delay`

* `ISOURCE_PWL` allows writing all the temporal current waveform using a PWL (Piecewise Linear). This requires the use of the `[PulseTransfer]` module to get the current waveform. A delay can also be added using `t_delay`

* In order to lightweight the generated netlists, the `ISOURCE_PULSE` can be selected: it uses the total collected charge Q (instead of the current pulse). Charge and current are linked by $ Q = \int I(t)dt $. The current pulse is set with the parameters `t_delay`, `t_rise`, `t_width` and `t_fall`. The following equation is then used to determine the current: $ I=\frac{Q}{\frac{t_{rise}+t_{fall}}{2}+t_{width}} $

The generated netlist file name can be configured with a prefix taken from the `file_name` parameter, and contains the number of the event the netlist was generated for. The file extension is taken from the input netlist template file.

* `target`: Syntax for the additional data to be written in the netlist, either `SPECTRE` or `SPICE`.

* `netlist_template`: Location of file containing the netlist template of the circuit in one of the supported formats.

* `file_name` : Generated netlist prefix name to which the event number is added as suffix. Defaults to `output_netlist_event_`.

* `source_type`: Type of current source to be used, `ISOURCE` and `ISOURCE_PULSE`. Defaults to `ISOURCE_PULSE`.

* `source_type`: Type of current source to be used, `ISOURCE_PWL` and `ISOURCE_PULSE`.

* `source_name`: Name of the current source instance in the netlist.

* `subckt_name`: Name of the circuit the source is connected to.

* `common_nets`: Nets shared between the pixels.

## Usage

A possible configuration is using a `ISOURCE` and the `SPICE` syntax, requiring the collecting electrode capacitance:

A possible configuration is using a `ISOURCE_PWL` and the `SPICE` syntax, requiring the collecting electrode capacitance:

```ini

[NetlistWriter]

target = SPICE

netlist_template = "front_end.asc"

source_type = ISOURCE

source_type = ISOURCE_PWL

source_name = Instance_source

subckt_name = Instance_front_end

common_nets = Comp_vref, SUB, VDDA, VSSA, Vfbk

t_rise = 5ns

t_width = 20ns

t_fall = 5ns

source_name = Instance_pulse

source_name = Instance_source

subckt_name = Instance_front_end

common_nets = Comp_vref, SUB, VDDA, VSSA, Vfbk

waveform_to_save = Comp_vout