Add Azure Database offerings

[teszes]

Adds Azure SQL and NoSQL offernings, namely:

• CosmosDB accounts
• SQL CosmosDB tables
• Cassandra CosmosDB tables
• Gremlin CosmosDB tables
• MongoDB CosmosDB tables
• Azure SQL databases
• MSSQL databases
• MySQL databases
• MariaDB databases
• PostgreSQL databases

[ianmiell]

LGTM Will merge and resolve conflicts by hand.

[teszes]

Rebased from most recent main branch with added fix for Cassandra

[ttarczynski]

Another error when running terraform apply:

azurerm_postgresql_server.changeme_simple_postgresql_server: Creating...
╷
│ Error: creating PostgreSQL Server "changeme-simple-postgresql-database-name" (Resource Group "changeme-simple-postgresql-database-resource-group"): postgresql.ServersClient#Create: Failure sending request: StatusCode=0 -- Original Error: Code="InvalidUserName" Message="'changeme-admin-u' is not a valid name because it contains invalid characters."
│ 
│   with azurerm_postgresql_server.changeme_simple_postgresql_server,
│   on main.tf line 36, in resource "azurerm_postgresql_server" "changeme_simple_postgresql_server":
│   36: resource "azurerm_postgresql_server" "changeme_simple_postgresql_server" ***
│ 
╵
/home/runner/work/terraform-examples/terraform-examples/azurerm/azurerm_postgresql_server/simple

I'll add a fix for it.