Replace config file string with a constant of the path

[SteveDMurphy]

Closes #932

Code Changes

• Replace "fidesctl.toml" with DEFAULT_CONFIG_PATH

Steps to Confirm

• A local install of fidesctl can read the config and start the webserver

Pre-Merge Checklist

• All CI Pipelines Succeeded
• Documentation Updated:
  • documentation complete, or draft/outline provided (tag docs-team to complete/review on this branch)
  • documentation issue created (tag docs-team to complete issue separately)
• Issue Requirements are Met
• Relevant Follow-Up Issues Created
• Update CHANGELOG.md

Description Of Changes

Another hangup that keeps being found here is the need to manually add the port to the default config. Maybe worth taking a look there to ease startup steps/pain?

I think a good test for this may be to try and validate the webserver without passing the config, but not sure if that makes sense or not as of yet

Testing this PR requires a running db, so executing docker compose up -d fidesctl-db is a prereq

[sanders41]

Good catch!

[ThomasLaPiana]

@SteveDMurphy I totally hit this bug the other day and made a mental note to go back and figure out the cause! Thank you!