Add support of environment variable to set CLI arguments/options

[sebastien-marichal]

For context see this discuss post (internal link).

The goal is to add the support of environment variables to set the options of the SonarScanner for .NET. Here is a list of such environment variables and their options counterpart:

• SONAR_TOKEN for the sonar.token option
• SONAR_HOST_URL for the sonar.host.url option
• SONAR_ORGANIZATION for the sonar.organization option

Other scanners (maybe not all) support setting those options through the environment variables above.

During implementation, the order of precedence of the arguments/options provider should be clearly defined and aligned with other scanners.

Precedence

Those variables do not depend on anything (such as the SQ server), so generic precedence (taken from MS Documentation) can be applied (from highest to lowest priority):

• CLI arguments
• Envirnoment variables
• Configuration files (see FilePropertyProvider property provider)

[gregory-paidis-sonarsource]

Coming from this discuss post, we should also support, as mentioned here:

• SONAR_SCANNER_JAVA_EXE_PATH
• SONAR_SCANNER_SKIP_AUTO_PROVISIONING
• SONAR_SCANNER_OS
• SONAR_SCANNER_ARCH

[costin-zaharia-sonarsource]

See also: https://github.com/SonarSource/sonar-scanner-msbuild/issues/1961

[costin-zaharia-sonarsource]

And also SONAR_USER_HOME