https://apache.org/licenses/LICENSE-2.0 lays out the correct way to apply the Apache 2.0 license to a work.

There is a section named "HOW TO APPLY THE APACHE LICENSE TO YOUR WORK". It says that applying the license to a work is easy: "Include a copy of the Apache License, typically in a file called LICENSE, in your work".

However, in the Solana repo, the contents of the file LICENSE is NOT a copy of the Apache 2.0 license. Instead, it is the text mention further down on that page, that is intended to be used as a SECTION within a specific FILE of a work, with the goal of applying the Apache license only to that SPECIFIC FILE.

This PR corrects these issue and places the correct contents of the Apache 2.0 license, as per https://apache.org/licenses/LICENSE-2.0, into the LICENSE file.