Investigate using pre-installed func core tools rather than downloading to user home dir

**Is your feature request related to a problem? Please describe.**
Downloading the func core tools binary is bloating user disk space under $HOME/.swa/core-tools/$FUNC_VERSION

**Describe the solution you'd like**
In the scenario where it is already installed, we should check if core tools is already available on the user's machine and use that rather than downloading to the home directory

**Describe alternatives you've considered**
We can also consider using the minified releases of core tools which will take up less space in the user's home dir

**Additional context**
Changes should be made in this file: https://github.com/Azure/static-web-apps-cli/blob/main/src/core/func-core-tools.ts