record sampler informations in the material file

The main goal of this change is to have "ugly" code only in filamat.
In particular, the sampler binding information is now recorded
into the material file and used on the filament side to inform the
backend.

This means that on the filament side we only have generic code with
all the "uglyness" in filamat. In particular SamplerBindingMap and
SibGenerator now only exist in filamat.

Files of greater interest:
Material.cpp, MaterialBuilder.cpp

libs/filabridge/src/SamplerInterfaceBlock.cpp

@@ -46,7 +46,7 @@ SamplerInterfaceBlock::Builder& SamplerInterfaceBlock::Builder::add(
         std::string_view samplerName, Type type, Format format,
         Precision precision, bool multisample) noexcept {
     mEntries.push_back({
-            { samplerName.data(), samplerName.size() },
+            { samplerName.data(), samplerName.size() }, { },
             uint8_t(mEntries.size()), type, format, precision, multisample });
     return *this;
 }
@@ -84,6 +84,7 @@ SamplerInterfaceBlock::SamplerInterfaceBlock(Builder const& builder) noexcept
         assert_invariant(i == e.offset);
         SamplerInfo& info = samplersInfoList[i++];
         info = e;
+        info.uniformName = generateUniformName(mName.c_str(), e.name.c_str());
         infoMap[{ info.name.data(), info.name.size() }] = info.offset; // info.name.c_str() guaranteed constant
     }
     assert_invariant(i == samplersInfoList.size());
@@ -97,7 +98,7 @@ const SamplerInterfaceBlock::SamplerInfo* SamplerInterfaceBlock::getSamplerInfo(
     return &mSamplersInfoList[pos->second];
 }
 
-utils::CString SamplerInterfaceBlock::getUniformName(const char* group, const char* sampler) noexcept {
+utils::CString SamplerInterfaceBlock::generateUniformName(const char* group, const char* sampler) noexcept {
     char uniformName[256];
 
     // sampler interface block name