Add framework-arduinoespressif32-libs SDK to platform and load when referenced by platform package

Author: sgryphon

platform.json

@@ -81,6 +81,12 @@
       "owner": "platformio",
       "version": "~3.20014.0"
     },
+    "framework-arduinoespressif32-libs": {
+      "type": "sdk",
+      "optional": true,
+      "owner": "espressif",
+      "version": "~5.1.0"
+    },
     "framework-arduino-mbcwb": {
       "type": "framework",
       "optional": true,

platform.py

@@ -342,6 +342,7 @@ def _parse_version(original_version):
             )
 
         toolchain_remap = {
+            "esp32-arduino-libs": "framework-arduinoespressif32-libs",
             "xtensa-esp32-elf-gcc": "toolchain-xtensa-esp32",
             "xtensa-esp32s2-elf-gcc": "toolchain-xtensa-esp32s2",
             "xtensa-esp32s3-elf-gcc": "toolchain-xtensa-esp32s3",
@@ -401,6 +402,8 @@ def configure_arduino_toolchains(self, package_index):
             self.packages[toolchain_package]["version"] = version
             self.packages[toolchain_package]["owner"] = "espressif"
             self.packages[toolchain_package]["type"] = "toolchain"
+            if (toolchain_package == "framework-arduinoespressif32-libs"):
+                self.packages[toolchain_package]["optional"] = False
 
     def configure_upstream_arduino_packages(self, url_items):
         framework_index_file = os.path.join(