Rename SA_PASSWORD to MSSQL_SA_PASSWORD as SA_PASSWORD is deprecated

[jedla97]

Updating SA_PASSWORD to MSSQL_SA_PASSWORD as SA_PASSWORD is marked deprecated for some time (I see this note in MSSQL 2017 docs). To see that note you can look here https://learn.microsoft.com/en-us/sql/linux/quickstart-install-connect-docker?view=sql-server-ver16&tabs=cli&pivots=cs1-bash#run-the-container-2

[eddumelendez]

Thanks for your contribution, @jedla97 ! Do you know if there is a specific version where that env var was added? Just asking in order to see if we can avoid breaking changes to consumers

[jedla97]

@eddumelendez I didn't find it in release notes, but I run it with 2017 version and it work start fine. As I didn't find 2016 version I can say for sure it will be working there. By https://endoflife.date/mssqlserver the 2016 have only security support.

[eddumelendez]

Thanks, @jedla97 !