wireplumber: Add equalizer for Beyerdynamic DT1990 with balanced pads

Parametric Equalizer configuration was generated by running the below
command.

```bash
python -m autoeq --input-file="measurements/oratory1990/data/over-ear/Beyerdynamic DT 1990 (balanced earpads).csv" --output-dir="dt1990-results" --target="targets/Diffuse field 5128.csv" --parametric-eq --fs=44100,48000
```

wireplumber/.config/wireplumber/wireplumber.conf.d/custom.conf

@@ -3,6 +3,10 @@ wireplumber.components = [
     name = equalizer/dt770.lua, type = script/lua
     provides = equalizer.dt770
   }
+  {
+    name = equalizer/dt1990-balanced-diffuse.lua, type = script/lua
+    provides = equalizer.dt1990-bd
+  }
   {
     name = equalizer/input-denoise.lua, type = script/lua
     provides = equalizer.input-denoise
@@ -16,6 +20,7 @@ wireplumber.components = [
 wireplumber.profiles = {
   main = {
     equalizer.dt770         = required
+    equalizer.dt1990-bd     = required
     equalizer.input-denoise = required
     equalizer.zero2         = required
   }

wireplumber/.local/share/wireplumber/scripts/equalizer/dt1990-balanced-diffuse.lua

@@ -0,0 +1,111 @@
+-- Generated by EQ'ing DT1990 (balanced pads) frequency response to the
+-- Diffuse Field target curve using AutoEq.
+-- luacheck: ignore 111 113
+local args = {
+  ["node.description"] = "DT1990 (Balanced) Diffuse Field",
+  ["media.name"]       = "DT1990 (Balanced) Diffuse Field",
+  ["audio.position"]   = Json.Array { "FL", "FR" },
+  ["audio.channels"]   = 2,
+}
+
+args["filter.graph"] = Json.Object {
+  nodes = Json.Array {
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_1",
+      label   = "bq_highshelf",
+      control = Json.Object { Freq = 0, Gain = -6.1, Q = 1.0 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_2",
+      label   = "bq_lowshelf",
+      control = Json.Object { Freq = 105, Gain = -5.2, Q = 0.7 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_3",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 206, Gain = -5.3, Q = 0.51 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_4",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 4532, Gain = 5.5, Q = 0.41 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_5",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 791, Gain = 2.0, Q = 1.43 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_6",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 6829, Gain = -3.8, Q = 2.04 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_7",
+      label   = "bq_highshelf",
+      control = Json.Object { Freq = 10000, Gain = 3.1, Q = 0.70 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_8",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 8944, Gain = -1.4, Q = 2.88 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_9",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 3751, Gain = -1.6, Q = 5.97 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_10",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 4458, Gain = 1.5, Q = 6.00 },
+    },
+    Json.Object {
+      type    = "builtin",
+      name    = "eq_band_11",
+      label   = "bq_peaking",
+      control = Json.Object { Freq = 39, Gain = -0.2, Q = 1.88 },
+    },
+  },
+  links = Json.Array {
+    Json.Object { output = "eq_band_1:Out" , input = "eq_band_2:In"  },
+    Json.Object { output = "eq_band_2:Out" , input = "eq_band_3:In"  },
+    Json.Object { output = "eq_band_3:Out" , input = "eq_band_4:In"  },
+    Json.Object { output = "eq_band_4:Out" , input = "eq_band_5:In"  },
+    Json.Object { output = "eq_band_5:Out" , input = "eq_band_6:In"  },
+    Json.Object { output = "eq_band_6:Out" , input = "eq_band_7:In"  },
+    Json.Object { output = "eq_band_7:Out" , input = "eq_band_8:In"  },
+    Json.Object { output = "eq_band_8:Out" , input = "eq_band_9:In"  },
+    Json.Object { output = "eq_band_9:Out" , input = "eq_band_10:In" },
+    Json.Object { output = "eq_band_10:Out", input = "eq_band_11:In" },
+  },
+}
+
+args["capture.props"] = Json.Object {
+  ["node.name"]   = "dt1990_balanced_diffuse_effect_input.eq11",
+  ["media.class"] = "Audio/Sink",
+}
+
+args["playback.props"] = Json.Object {
+  ["node.name"]    = "dt1990_balanced_diffuse_effect_output.eq11",
+  ["node.passive"] = true,
+}
+
+local args_json   = Json.Object(args)
+local args_string = args_json:get_data()
+local properties  = {}
+
+print("Loading DT1990 Diffuse Field Equalizer Sink with arguments = ")
+print(args_string)
+
+filter_chain = LocalModule("libpipewire-module-filter-chain", args_string, properties)