Expose headers required for custom nwsync usage

[jhett12321]

Regarding this feature that was added to the base game a while back:

- Dedicated servers can now load their module data from a specially prepared NWSync repository, instead of having to have a copy of the module and hak files. (This mainly benefits big servers that have a CI/CD pipeline set up.)
- Added argument -moduleurl, from which the module data will be sourced
- Added a new optional argument -modulehash; which is considered to be `latest` if omitted
- Generate the server/module repository with --with-module
- You can reuse the public repository to save on duplication/disk space; or use a separate/private one. If you reuse the same repository and do not want to leak the module data, turn off http content listing and write the data with --no-latest.
- Data is stored in SERVERHOME/nwsync (this works the same as on the client). It will auto-prune old data if the group_id matches. The rest is left up to you.

I want to make an NWNX tweak that allows to run this in a mixed mode. So you would load a .mod file, but additional content would be loaded from a standard nwsync repo (without --with-module) instead of hak files. Or a mix of both hak files, and the nwsync repo.

This is not possible right now as the following structures and methods do not exist in NWNXLib, or are incomplete. Could these please be exposed?

• NWSync::CNWCSync
• Hash::SHA1
• NWSync::CNWCSync::Progress
• InstanceLookup::List
• CNWSync
• HttpBufferRef
• HttpUrl
• SimplyCopyingHttpBufferReceiver
• HttpConnection
• HttpAuthorizer
• CExoResMan::GetNWSync