[skip changelog] Improve wording of docs introduction (#1200)

The introductory sentence of the documentation homepage is the first thing the user may see when discovering Arduino
CLI. For this reason, it's important for it to quickly and clearly convey what Arduino CLI is. Toward that goal, the
following changes are made:

- Use more understandable terms
- Rearrange features list in the order of typical usage (install dependencies, compile, upload)

Author: per1234

Diff for: README.md

@@ -2,8 +2,8 @@
 
 ![cli-logo](./docs/img/CLI_Logo_small.png)
 
-Arduino CLI is an all-in-one solution that provides builder, Boards/Library Manager, uploader, discovery and many other
-tools needed to use any Arduino compatible board and platforms.
+Arduino CLI is an all-in-one solution that provides Boards/Library Managers, sketch builder, board detection, uploader,
+and many other tools needed to use any Arduino compatible board and platform.
 
 [![tests-badge]](https://github.com/Arduino/arduino-cli/actions?workflow=test)
 [![nightly-badge]](https://github.com/Arduino/arduino-cli/actions?workflow=nightly)

Diff for: docs/index.md

@@ -1,5 +1,5 @@
-Arduino CLI is an all-in-one solution that provides builder, Boards/Library Manager, uploader, discovery and many other
-tools needed to use any Arduino compatible board and platforms.
+Arduino CLI is an all-in-one solution that provides Boards/Library Managers, sketch builder, board detection, uploader,
+and many other tools needed to use any Arduino compatible board and platform.
 
 ## Installation