`ArgsParser` and `AboutDialog` had the same procedure to read the
version from `/res/version.ini`. Now they use the `SERENITY_VERSION`
string by default.
This commit refactored the version-reading utility to the new
`Core::Version` namespace.
Before, `AboutDialog` and `ArgsParser` read from a build-time created
file called `/res/version.ini`. This caused problems with utilities
unveiling specific paths leaving the version file unaccessible.
This commit hard-codes a serenity version in `LibCore`, and use it in
`ArgsParser` and `AboutDialog`.
The previous version contained the hash of the last GIT commit, this is
omitted for the default use for the sake of simplicity.