#### ⚠️ targets #10051
## Summary of the Pull Request
This PR does one big, primary thing. It removes all the constructors from any TerminalConnections, and changes them to use an `Initialize` method that accepts a `ValueSet` of properties.
Why?
For the upcoming window/content process work, we'll need the content process to be able to initialize the connection _in the content process_. However, the window process will be the one that knows what type of connection to make. Enter `ConnectionInformation`. This class will let us specify the class name of the type we want to create, and a set of settings to use when initializing that connection.
**IMPORTANT**: As a part of this, the constructor for a connection must have 0 arguments. `RoActivateInstance` lets you just conjure a WinRT type just by class name, but that class must have a 0 arg ctor. Hence the need for `Initialize`, to actually pass the settings.
We're using a `ValueSet` here because it's basically a json blob, with more steps. In the future, when extension authors want to have custom connections, we can always deserialize the json into a `ValueSet`, pass it to their connection's `Initialize`, and let then get what they need out of it.
## References
* Tear-out: #1256
* Megathread: #5000
* Project: https://github.com/microsoft/terminal/projects/5
## PR Checklist
* [x] Closes https://github.com/microsoft/terminal/projects/5#card-50760298
* [x] I work here
* [n/a] Tests added/passed
* [n/a] Requires documentation to be updated
## Detailed Description of the Pull Request / Additional comments
`ConnectionInformation` was included as a part of this PR, to demonstrate how this will eventually be used. `ConnectionInformation` is not _currently_ used.
## Validation Steps Performed
It still builds and runs.
This PR defines a series of `NOSOMETHING` macros in PCHs, in order to
prevent `windows.h` from bringing a lot of rarely used things into the
project.
Theoretically this should make PCH generation and overall complication
faster, but I didn't really benchmark the speed.
Another benefit would be reducing the symbol noises caused by
`windows.h`.
This commit introduces a small console-subsystem application whose sole
job is to consume TerminalConnection.dll and hook it up to something
other than Terminal. It is 99% of the way to a generic solution.
I've introduced a stopgap in TerminalPage that makes sure we launch
TerminalAzBridge using ConptyConnection instead of AzureConnection.
As a bonus, this commit includes a class whose sole job it is to make
reading VT input off a console handle not terrible. It returns you a
string and dispatches window size change callbacks.
Fixes#2267.
Fixes#4589.
Related to #2266 (since pwsh needs better VT).
