Meta: Update jakt build support for fully bootstrapped compiler

Remove the Corrosion dependency, and use the now-builtin
add_jakt_executable function from the Jakt install rules to build our
example application.

By using find_package(Jakt), we now have to set ENABLE_JAKT manually on
both serenity and Lagom at the same time, so the preferred method to do
this for now is:

    cmake -B Build/superbuild<arch><toolchain> \
          -S Meta/CMake/Superbuild \
          -DENABLE_JAKT=ON \
          -DJAKT_SOURCE_DIR=/path/to/jakt

Where omitting JAKT_SOURCE_DIR will still pull from the main branch of
SerenityOS/jakt. This can be done after runing Meta/serenity.sh run.

Meta/CMake/jakt.cmake

@@ -4,14 +4,6 @@
 
 include(FetchContent)
 
-FetchContent_Declare(
-  Corrosion
-  GIT_REPOSITORY https://github.com/corrosion-rs/corrosion.git
-  GIT_TAG v0.2.1
-)
-
-FetchContent_MakeAvailable(Corrosion)
-
 FetchContent_Declare(jakt
     GIT_REPOSITORY https://github.com/SerenityOS/jakt.git
     GIT_TAG main
@@ -24,17 +16,5 @@ if (JAKT_SOURCE_DIR)
     message(STATUS "Using pre-existing JAKT_SOURCE_DIR: ${JAKT_SOURCE_DIR}")
 endif()
 
-FetchContent_GetProperties(jakt)
-if (NOT jakt_POPULATED)
-    FetchContent_Populate(jakt)
-    corrosion_import_crate(MANIFEST_PATH "${jakt_SOURCE_DIR}/Cargo.toml")
-    corrosion_set_hostbuild(jakt)
-    add_executable(Lagom::jakt ALIAS jakt)
-    corrosion_install(TARGETS jakt RUNTIME COMPONENT Lagom_Runtime)
-    # NOTE: See lagom-install-config.cmake for hax required to get Lagom::jakt to show up on install
-    install(DIRECTORY "${jakt_SOURCE_DIR}/runtime"
-            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/jakt
-            FILES_MATCHING PATTERN "*.h"
-                           PATTERN "*.cpp"
-                           PATTERN "utility")
-endif()
+set(JAKT_BUILD_TESTING OFF)
+FetchContent_MakeAvailable(jakt)