Replace PdoEndpoint with native SqlServerEndpoint

[raffis]

Description

Is:
Currently there is a PdoEndpoint which has several disadvantages.
For example since multiple drivers are supported they still have different sql implementations.
For instance chunking response is different from MySQL to an SQL Server. There is no LIMIT in the SqlServer world.

Should:
Implement native MS SqlServer endpoint. Drop PDO support.

tubee server version

v1.0.0-beta1

tubee cli client version (If related)

PHP version

Operating system

Webserver