Generic Folder Matching installer

[Al12rs]

Closes #477

• This PR adds support for Top level mods like SKSE for SkyrimSE and LE (Support for installing SKSE in SkyrimSE and LE #477)
• Enhances support for Data level mods adding many more recognized paths and file types.
• It also already supports all other released bethesda games such as Fallout series, morrowind, VR versions etc.
• Installer is designed to be generic and reusable even for non bethesda games (see Design Code Reuse friendly solution for Game Support #420)
• Implemented GameCapabilities system as outlined in (Implement extensible system to allow games to have optional functionality #503)
• Removed old SkyrimInstaller since the new one should be able to handle many more mods (even at Data level).
• Updated tests to use the Generic installer

GameCapabilities

See #503 for all the objectives and rationale behind the system.

GenericFolderMatchInstaller

The idea is to have an installer that takes a list of recognizable folder targets and tries to match the content of a mod archive to that of one of the targets.

In the case of Bethesda games I just defined two targets (InstallFolderTarget), root level and Data, where Data is nested under the Root one.
Each target contains information to recognize it, such as known subfolders or extensions for files that reside at that level.

Most of the information regarding the known folders and extensions was taken from MO2, so it should be pretty valid.

Potential improvements:

I'm not completely happy with how the code structure turned out for now. I think the structure could be simplified a bit probably. I would have spent some more time tweaking and moving things around if we didn't want to get SKSE support done.

Some ideas I considered:

• Moving the helper methods of the Generic installer to InstallFolderTarget
• Making some of those part of an interface IInstallFolderTarget, e.g.: PathMatchesAnyTarget(), GetModFilesForTarget()
• Allowing games to implement IIinstallFolderTargets that use different data and behaviour.

But that felt like it would make the structure more complicated rather than simplifying it.

For capabilities I would like to consider using IServiceProvider for storing them inside games, but that needs some investigation for advantages/disadvantages.

I'm not completely happy with the names either.

I'm sure there is lots of room for improvements here so let me know of any suggestions.