[BOLT] Revise IDE folder structure (#89742)

Update the folder titles for targets in the monorepository that have not
seen taken care of for some time. These are the folders that targets are
organi

[BOLT] Revise IDE folder structure (#89742)

Update the folder titles for targets in the monorepository that have not
seen taken care of for some time. These are the folders that targets are
organized in Visual Studio and XCode (`set_property(TARGET <target>
PROPERTY FOLDER "<title>")`) when using the respective CMake's IDE
generator.

* Ensure that every target is in a folder
* Use a folder hierarchy with each LLVM subproject as a top-level folder
* Use consistent folder names between subprojects
* When using target-creating functions from AddLLVM.cmake, automatically
deduce the folder. This reduces the number of
`set_property`/`set_target_property`, but are still necessary when
`add_custom_target`, `add_executable`, `add_library`, etc. are used. A
LLVM_SUBPROJECT_TITLE definition is used for that in each subproject's
root CMakeLists.txt.

show more ...

[BOLT][Docs] Add Sphinx documentation

Add stub Sphinx documentation, with configuration copy-pasted from lld and
index page converted from bolt/README.md.

Reviewed By: #bolt, rafauler

Differential

[BOLT][Docs] Add Sphinx documentation

Add stub Sphinx documentation, with configuration copy-pasted from lld and
index page converted from bolt/README.md.

Reviewed By: #bolt, rafauler

Differential Revision: https://reviews.llvm.org/D140156

show more ...

[BOLT][DOCS] Build doxygen documentation

Summary:
Added doxygen configuration files and CMake directives, copy-pasta from flang.

```cmake -G Ninja ../llvm-project/llvm \
-DLLVM_ENABLE_PROJECTS="b

[BOLT][DOCS] Build doxygen documentation

Summary:
Added doxygen configuration files and CMake directives, copy-pasta from flang.

```cmake -G Ninja ../llvm-project/llvm \
-DLLVM_ENABLE_PROJECTS="bolt" \
-DBOLT_INCLUDE_DOCS=YES \
-DLLVM_ENABLE_DOXYGEN=YES
ninja doxygen-bolt
```

(cherry picked from FBD33303249)

show more ...