chore(ci): Improve testing and style linting. Fix and update content.

[jstirnaman]

PR changes since last reviewed:

Updates CONTRIBUTING.md for testing and linting. Updates content and fixes content issues revealed by tests and linting. Updates migrate guide for testing. Support influxctl commands: monitor for auth URLs that the container tries to open in a browser, then open them in the host's browser. Skip tests for creating and deleting databases as namespaces aren't reusable. Make write/query examples more easily testable--adjusts Unix timestamps (line protocol) and query time bounds for testing Support for substituting additional placeholders during tests. Update management token and Management API info.

Previous changes:

Vale style improvements:

• Run Vale in a Docker container by running ./.ci/vale/vale.sh
• Define vale lint scripts in package.json. Lint added and changed files for products.
• Define error-level vale linting in the lint-staged configuration for staged files.
• Improve product-specific nomenclature checks (e.g. database vs bucket) and change alert level from error to warning until we can make checks for precise, fewer false positives
• Simplify vocab terms and allowed words lists.
• Fixes content errors revealed by vale.

Test fixes:

• Add python replacement for get-started database/bucket name
• Fixes race condition when deleting previous content:
  • Assign each product it's own test content volume instead of sharing a volume.
  • Delete existing content in the volume before copying test files.
  • Pros and cons, but I suspect a similar approach will be better when ported to Circle CI.