add "Compile and link statically to a bundled C library" example

[budziq]

Use cc-rs crate to compile and link statically to a bundled C library inside of a build.rs file.

Please note that it will be important to mention that this is a build time crate.
Most likely we will dedicate a separate (last) chapter like "build_time.md"

cc #236

[jaemk]

Note: The trust repo is itself a basic example that could be copied and simplified.

[budziq]

Right! @jaemk Would you be interested in taking lead on this example?

I see this as the first example that would have the longest explanation followed by the next 4 examples listed in #236 showing the possible minor differences (with much shorter descriptions)

[jaemk]

Sure! I can take a look at this tomorrow and setup a new build_tools file