WIP: Allow more powerful config file

[MrKevinWeiss]

TBD:

• Benchmarks
  • _attempted_value scaling
  • import scaling
  • invoke python
  • setting value with python vs select
• Tests
  • Set each value type/read
  • importing dirs
  • Error conditions

[MrKevinWeiss]

Benchmarks show that the python config file using eval go pretty slow.

Running some quick local tests that only use simple features such as if, else, and source I get:

Execution time for the regex version (1000 runs): 0.037437569997564424 seconds
Execution time for the ast version (1000 runs): 0.22356338799727382 seconds

If we really care about speed we would cripple the config language quite a bit to use just the regex (which is currently what is being used to parse). This would mean we need some limitations...