(cmake): improve package version number generation

What does this MR do?

• Added cmake helper script get_git_rev.cmake (from sight-deps) to find git tags, branch name, version...
• Updated cmake script to generate a SDK filename using the latest tag (or git revision, see command git describe --tags)
• Updated cmake script to add Sight version in app packages

How to test it?

⚠ before launching a ninja install, check that your install directory is empty ⚠

SDK

• configure sight with BUILD_SDK to ON
• and finally run:

> ninja install
> ninja package

Application

• configure sight with BUILD_SDK to OFF
• specify PROJECTS_TO_BUILD with an installable application (VRRender for example)
• and finally run:

> ninja install
> ninja package

Data

No required data

Some results

SDK

• A SDK archive file (tar.gz) is generated in build dir
• Example in debug on windows, when you are not on a tag:

sight-Debug-18.1.0-xxx-gxxxxx-win64.tar.gz generated

• Example in debug on windows on a tag:

sight-Debug-18.1.0-win64.tar.gz generated

Application

• A archive file is generated in build dir
• Example in debug on windows, when you are not on a tag:

VRRender-0.9-win64-Sight_18.1.0-437-g89507d1af.exe generated

• Example in debug on windows on a tag:

VRRender-0.9-win64-Sight_18.1.0.exe generated

Additional tests to run

• Generate on Windows
• Generate on Linux
• Generate on macOS

Associated issue

• Closes #267 (closed)
• Sight/sight#270