Use TypedData and CI-related fixes

[andyundso]

Closes #493

The main intention of this PR is to switch from using Data to TypedData in C-Land. Data is essentially a container object for Ruby to know that we allocate additional memory in C-Land for things outside of Rubys control, e.g. the entire FreeTDS client. TypedData gives the Ruby VM a couple more hints about what it deals with. I am sure there is more to that. Anyhow, Data is deprecated with Ruby 3.4, so consider this a preparation for adding Ruby 3.5 support.

Then a bunch of CI-related stuff arised, which I also fix in this PR:

• The artistic code style check currently runs endlessly, likely because of a broken download on their side. I'll open a PR there and re-activate the check hopefully soon.
• Installing the tiny_tds on Windows without the precompiled stuff fails on 2.7, 3.0 and 3.1 because of a dependency conflict. I am sure it is related to this bug, but I do not have the time or motivation to investigate how to fix this for these old versions.
• The PowerShell script now correctly restores the ports from the precompiled Ruby gem, which lead to another test failure, which I used as a chance to harmonise finding resources in the ports directory.