We need to clarify the documentation for running over multiple shards and update for new predicates functionalities

[mmcdermott]

Per #113, this is still causing confusion, and should be clarified.

[justin13601]

Add documentation for new predicates functionalities:

• [x] Separate predicates file for both aces-cli and python API
• [x] Other ways to define predicates
  • Constraint on other columns (ie. not code) using other_cols key which maps to a dictionary of column name and target value
  • Regex in the form of code: {regex: "..."} which will match any code that matches that regex
  • A list of targets in the form of code: {any: [code_1, code_2, ...]}