Add vcpkg installation instructions

[FrankXie05]

BehaviorTree.CPP is available as a port in vcpkg, a C++ library manager that simplifies installation for BehaviorTree.CPP and other project dependencies. Documenting the install process here will help users get started by providing a single set of commands to build BehaviorTree.CPP, ready to be included in their projects.

We also test whether our library ports build in various configurations (dynamic, static) on various platforms (OSX, Linux, Windows: x86, x64) to keep a wide coverage for users.

I'm a maintainer for vcpkg, and here is what the port script looks like. We try to keep the library maintained as close as possible to the original library.😊

[facontidavide]

I do not maintain vcpkg and I don't know who does.
Apparently the latest supported version is 4.1.1 that I DO NOT want to encourage people to use the old and buggy version.

[FrankXie05]

@facontidavide We will maintain BehaviorTree.CPP on vcpkg, and we will perform version update maintenance.
And I will update the version.

[FrankXie05]

The version on vcpkg has been update.

[facontidavide]

I bug problem I see there is this:

    -DBTCPP_GROOT_INTERFACE=OFF
    -DBTCPP_SQLITE_LOGGING=OFF

I know this makes it easier, but loosing those dependency is a big deal, in my opinion.

[FrankXie05]

I bug problem I see there is this:

    -DBTCPP_GROOT_INTERFACE=OFF
    -DBTCPP_SQLITE_LOGGING=OFF

I know this makes it easier, but loosing those dependency is a big deal, in my opinion.

These dependencies are mainly used for the construction of conan. I can solve it through patches, but this method only applies to vcpkg. I would like to ask if this method is allowed? 🫤

BTW, we may not maintain the conan problem, and my patch is just to change the dependency to vcpkg usage.

Here is the patch:
fix-conan.patch