Implements #6208

[rogin]

Enable reading the server name and environment name from environment variables. Utilized code from @jonbartels plugin.

[rogin]

Used a freshly built server under /server/setup.

Start server with java -jar .\mirth-server-launcher.jar, and bring the server down after each test.

Test 1: No envvars set. Start server. Complete the admin change password modal. Validate values are blank in UI.
Test 2: set envvar MC_SERVER_NAME = 'Staging'. Start server. Validate its value in UI.
Test 3: set envvar MC_ENV_NAME = 'Sys-001'. Start server. Validate both values in UI.
Test 4: set envvar MC_SERVER_NAME = 'Prod', MC_ENV_NAME = 'Sys-002'. Start server. Validate both values in UI.
Test 5: Unset envvars MC_SERVER_NAME and MC_ENV_NAME. Start server. Validate both values in UI are same used in test 4 (as they've been stored in DB).