[NGIO] Updating licensing aspects according REUSE specs

[lucaslasota]

Hello,

I am proposing some updates regarding copyright and licensing information. REUSE specifications intend to make licensing easier, setting one way to display all these legal information through comment headers on source files that can be human and machine readable.

Feel completely to adopt these specifications by merging this pull request.

REUSE Features

• SPDX copyright and license comment headers for all relevant files
• LICENSES directory with all licenses used on the repository
• DEP5 file to bulk-license entire directories

Files missing copyright and licensing information

The repository contains files with missing copyright and licensing information. For those I did not add any headers. Examples:

• pkg/systray/pid.go no copyright and license
• branding/templates/osx no year of creation

For these files would be necessary firstly to determine who is the copyright, the year and then the chosen license.

Bundled libraries

It is necessary to update the README with the information about the libraries that are being bundled and distributed into the binaries. I added the basic information on README. Please check if there is anything to be added.

DEP5 file for bulk-licensing

There are icons and arts which licensing information I added to the .reuse/dep5 file on repository root. However, there is another dep5 file in branding/templates/debian/copyright which relates (as far I understood) to all files. Please check the consistency of this file.

Further REUSE compliance

In case you find REUSE useful for Bitmask, we offer a wide range of tools to help you to continuously check and display compliance with the REUSE guidelines.

Hope that helps and thank you very much for the amazing job!