Add CLI & Env Variable Support for Aliases

[prikhi]

#14 added aliases to the config file, we should also figure out a format for passing them in as CLI options & through environmental variables.

Maybe allow multiple CLI flags like --some-flag JOURNAL_CURRENCY:ALPHAVANTAGE_TICKER to assemble the list, maybe a similar alias format deliminated with semicolons for the env var like SOME_VAR="JCUR1:ATICKER1;JCUR2:ATICKER2"