feat(server): allow ratelimiting to be explicitly disabled

[iainsproat]

Description & motivation

We may wish to enable the rate limiter in some testing environments, and we may wish to disable the rate limiter in some non-testing environments (e.g. development).

The rate limiter was previously implied based on whether NODE_ENV is 'test', which may not be desired behaviour.

Changes:

• allows rate limiter to be enabled or disabled explicitly via environment variable or helm chart.
• introduces RATELIMITER_ENABLED boolean environment variable, default is true.
• introduces helm chart parameter server.ratelimiting.enabled to configure the same, default is true.

To-do before merge:

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.
• I have added appropriate tests.
• I have updated or added relevant documentation.

References