Add CLI modules for PostgreSQL and TPC-H.

[lmwnshn]

This PR adds functionality for setting up the DBMS and obtaining benchmark data for Proto-X.

Some highlighted commands:

• benchmark tpch
  • generate-sf SF: generate table data for the given scale factor.
  • generate-workload WORKLOAD_NAME SEED_START SEED_STOP: generate a named workload that has TPC-H queries seeded with [SEED_START, SEED_STOP] inclusive. Accepts options to control which queries are included.
  • load-sf SF DBMS DBNAME: loads the specified table data (and creates indexes) into the relevant database.
• dbms postgres
  • clone: obtain the source code for our build of DBMS, also installs extensions
  • init-auth: create default authentication from the root config.yaml specifications
  • init-db DBNAME: create a new empty database with the specified name
  • init-pgdata: (re-)initialize the PGDATA folder
  • run-sql-file SQL_PATH: run the specified SQL file
  • start: (re-)start the DBMS
  • stop: stop the DBMS

The file ./test/wan_test.sh demonstrates a complete run that includes (1) setting up the DBMS, (2) setting up TPC-H, (3) obtaining training data for Proto-X embeddings, (4) selecting the best Proto-X embedding.

[lmwnshn]

This PR assumes that #12 and #13 will merge first.