sdbus++: events: create event classes

Generate an equivalent amount of exception class as the `errors.yaml`
supported and convert the examples to use it.

Tested:

```
‣ Type=error  Endian=l  Flags=1  Version=1 Cookie=9  ReplyCookie=2  Timestamp="Tue 2024-09-17 18:21:35.649674 UTC"
  Sender=:1.2489  Destination=:1.2495
  ErrorName=net.poettering.Calculator.DivisionByZero  ErrorMessage="Attempted to divide by zero."
  UniqueName=:1.2489
  MESSAGE "s" {
          STRING "Attempted to divide by zero.";
  };
```

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I4b2671838639d1e8be1ccdf655b699a98b9c2116
diff --git a/example/calculator-aserver.cpp b/example/calculator-aserver.cpp
index 33a582a..7a5051e 100644
--- a/example/calculator-aserver.cpp
+++ b/example/calculator-aserver.cpp
@@ -21,7 +21,7 @@
     auto method_call(divide_t, auto x,
                      auto y) -> sdbusplus::async::task<divide_t::return_type>
     {
-        using sdbusplus::error::net::poettering::calculator::DivisionByZero;
+        using sdbusplus::error::net::poettering::Calculator::DivisionByZero;
         if (y == 0)
         {
             status(State::Error);
diff --git a/example/calculator-server.cpp b/example/calculator-server.cpp
index 7ee4218..2d0efca 100644
--- a/example/calculator-server.cpp
+++ b/example/calculator-server.cpp
@@ -1,5 +1,4 @@
 #include <net/poettering/Calculator/client.hpp>
-#include <net/poettering/Calculator/error.hpp>
 #include <net/poettering/Calculator/server.hpp>
 #include <sdbusplus/server.hpp>
 
@@ -29,7 +28,7 @@
      */
     int64_t divide(int64_t x, int64_t y) override
     {
-        using sdbusplus::error::net::poettering::calculator::DivisionByZero;
+        using sdbusplus::error::net::poettering::Calculator::DivisionByZero;
         if (y == 0)
         {
             status(State::Error);
diff --git a/example/yaml/net/poettering/Calculator.interface.yaml b/example/yaml/net/poettering/Calculator.interface.yaml
index f130e59..affc2d4 100644
--- a/example/yaml/net/poettering/Calculator.interface.yaml
+++ b/example/yaml/net/poettering/Calculator.interface.yaml
@@ -40,7 +40,7 @@
             description: >
                 The result of (x/y).
       errors:
-          - self.Error.DivisionByZero
+          - self.DivisionByZero
     - name: Clear
       flags:
           - unprivileged
@@ -65,7 +65,7 @@
       description: >
           The name of the owner of the Calculator.
       errors:
-          - self.Error.PermissionDenied
+          - self.PermissionDenied
 signals:
     - name: Cleared
       description: >