Introduced in 2e35b07 when moving to github releases, removing it since
it's been 20 months already.
Added temporary clean up step to remove previous installation.
I've found this commit 4400a6e that was introducing this option to the main cmake, but I'm not sure if it ever was propagated to the main branch or was reverted inside one of the merges.
But anyway, `USE_STATIC_MSVC_RUNTIME` is currently used only in svgfill, not used in the main cmake and works out of sync with main cmake (it sets `Boost_USE_STATIC_RUNTIME` to `OFF` instead of guard+setting it to `ON`).
So removing this option and syncing the code.
Resolves the warnings below:
```
CMake Deprecation Warning at CMakeLists.txt:207 (message):
Use SQLite3_INCLUDE_DIR instead of SQLITE3_INCLUDE_DIR
CMake Deprecation Warning at CMakeLists.txt:211 (message):
Use SQLite3_LIBRARY instead of SQLITE3_LIBRARY
```
It was introduced a (very) long time ago (c7bf03e), was barely changed since then and seems unused by now.
Apparently it was used mainly to get installation's Python to PATH (`set PATH=%PYTHONHOME%;%PATH%`). It was also setting and env variables based on the cache as a side effect.
If needed, we'll be able reintroduce it later, delegating most of the logic to Python.
`TARGET_ARCH` has exactly the same values as `VS_PLATFORM` - "x64", "ARM", "ARM64") except it has `x86` instead of `Win32`, but this value is never actually used, so both variables end up using interchangeably, making code harder to reason about - you needed to remember that they're exactly the same except the case when the variable is passed directly to VS (either through `cmake -A` or some `msbuild` command), then user must use `VS_PLATFORM`. So we might just use one variable always.
`START` is set to `0` for "amd64" / "x64" and `1` in all other cases, effectively just skipping `GENERATORS[0]` in case when "amd64" or "x64" is present.
Which is now useless, since `GENERATORS[0]` doesn't exist anymore.
They were added awhile ago in 67666ed for overcoming some win32 issues, which is not around anymore.
And now `VS_HOST` is never set (and therefore `VS_TOOLSET_HOST` is always empty too) and likely to be never used.
CI was failing:
```
The system library `dbus-1` required by crate `libdbus-sys` was not found.
The file `dbus-1.pc` needs to be installed and the PKG_CONFIG_PATH environment variable must contain its parent directory.
The PKG_CONFIG_PATH environment variable is not set.
```
There was an error building a standalone ifcwrap when previously built IfcOpenShell had rocksdb - `_ifcopenshell_wrapper.cpython-314-x86_64-linux-gnu.so: undefined symbol: _ZTV17RocksDbSerializer`.
`IFOPSH_WITH_ROCKSDB` propagated to the build, requiring rocksdb symbols, but `WITH_ROCKSDB` wasn't set and `document_serializer_rdb` target wasn't provided.
Otherwise it will never be able to reach standalone ifcwrap build as in this case ifcopenshell is built first as a dependency without `BUILD_IFCPYTHON`.
Andrej730