[fix] Fixes installation for SQL Azure. Fixes #5293

Removed commented out select lines in SQL server driver and query file.
SQL Azure updates.
- Can now install on MS SQL
- Will create a SQL Server DB if one does not exist
- Can run the CMS and Admin on SQL Server
Codestyle
[imp] Add Minimum Stability feature in Joomla! Extensions Update. Closes #5201
[imp] Use constants to improve readability. Part of #5201
[fix] Clear limit and offset for all JDatabaseQuery objects. Fixes #4485
[imp] do not disable sites when connection fails
[imp] enable language update site on Find Languages click
[imp] show disabled update sites warning when searching for extension updates77
Merge pull request #5296 from phproberto/update-sites-language

Update sites improvements
[fix] Fixes module "Related Item" in PostgreSQL. Closes #5243
Merge branch 'staging' of https://github.com/joomla/joomla-cms into staging