docs/building: modernise libuv mentions

libuv is used by the CPP-Rust Driver only for tests and some of
the examples, so let's state that clearly.
Also, let's remove exact build instructions for libuv, as they are prone
to change with new releases and it's better for the user to refer to
the libuv documentation.

Author: wprzytula

docs/source/topics/building.md

@@ -20,13 +20,17 @@ ScyllaDB does not support these platforms.
 The C/C++ driver depends on the following software:
 
 * [CMake] v2.6.4+
-* [libuv] 1.x
+* [libuv] 1.x (only for tests and examples, not required for the driver itself)
 * [OpenSSL] v1.0.x or v1.1.x \*
 
 __\*__ Use the `CASS_USE_OPENSSL` CMake option to enable/disable OpenSSL
          support. Disabling this option will disable SSL/TLS protocol support
          within the driver; defaults to `On`.
 
+Note that only `CMake` is mandatory for building the driver. The others:
+- `libuv` is only required for building tests and some of the examples, not the driver itself.
+- `OpenSSL` is only required if you want to enable TLS support in the driver.
+
 ## Linux/Mac OS
 
 The driver is known to build on CentOS/RHEL 6/7/8, Mac OS X 10.10/10.11 (Yosemite
@@ -67,9 +71,9 @@ brew install autoconf automake cmake libtool
 
 #### libuv
 
-libuv v1.x should be used in order to ensure all features of the C/C++ driver
-are available. When using a package manager for your operating system make sure
-you install v1.x. Recent package repositories tend to have it available.
+**libuv is required only for tests and examples, not required for the driver itself.**
+libuv v1.x is recommended. When using a package manager for your operating system,
+make sure you install v1.x.
 
 ##### Ubuntu
 
@@ -103,17 +107,8 @@ brew install libuv
 _The following procedures should be performed if packages are not available for
 your system._
 
-```bash
-pushd /tmp
-wget http://dist.libuv.org/dist/v1.34.0/libuv-v1.35.0.tar.gz
-tar xzf libuv-v1.35.0.tar.gz
-pushd libuv-v1.35.0
-sh autogen.sh
-./configure
-make install
-popd
-popd
-```
+Browse [https://dist.libuv.org/dist/] and download the newest stable version available.
+Follow the instructions in the downloaded package to build and install it.
 
 #### OpenSSL