Licensing

[Retr0-code]

Problem

• Add licensing to source code and headers

/*
	Copyright (C) 2023 Nikita Retr0-code Korneev

    Pong-RL is free software: you can redistribute, modify it
    under the terms of the GNU Affero General Public License version 3.

    You should have received a copy of GNU Affero General Public License
    version 3 along with Pong-RL.
    If not, see <https://www.gnu.org/licenses/agpl-3.0.html>.

Pong-RL - https://github.com/Retr0-code/Pong-RL
----

	References used:
 <links to sources>
----

	<file description>
*/

• Add licensing banner on start