feat: Added CSV, TSV and JSON as export options for Find results (#1673)

### Problem description
The default result export functionality of the Find tool is limited to
only exporting data in a nonstandard text format. This PR adds support
for exporting the results in CSV, TSV or JSON format. The PR also
removes the old format.

### Implementation description
I added the classes `ExportFormatter`, `ExportFormatterCsv`,
`ExportFormatterTsv` and `ExportFormatterJson`, with similar
implementations to the pattern data exporters.

~~I also moved the `ViewFind::Occurrence` class into
`hex/helpers/types.hh`, so the exporters can access it.~~

### Screenshots

![image](https://github.com/WerWolv/ImHex/assets/45818400/c7a1016b-6494-416d-a963-86484952837c)

### Additional things
Another small change I made is moving the "{} entries found" line on the
same line as the Search and Reset buttons. I think it looks cleaner this
way, but if anyone disagrees, I can revert it.

---------

Co-authored-by: WerWolv <werwolv98@gmail.com>

plugins/builtin/source/content/main_menu_items.cpp

@@ -210,7 +210,7 @@ namespace hex::plugin::builtin {
         }
 
         void drawExportLanguageMenu() {
-            for (const auto &formatter : ContentRegistry::DataFormatter::impl::getEntries()) {
+            for (const auto &formatter : ContentRegistry::DataFormatter::impl::getExportMenuEntries()) {
                 if (ImGui::MenuItem(Lang(formatter.unlocalizedName), nullptr, false, ImHexApi::Provider::get()->getActualSize() > 0)) {
                     fs::openFileBrowser(fs::DialogMode::Save, {}, [&formatter](const auto &path) {
                         TaskManager::createTask("Exporting data", TaskManager::NoProgress, [&formatter, path](auto&){