feature: support useragent and ip allow/blocking, and namespace interval idling overrides

[shreddedbacon]

This adds support for being able to define

• allowing IP addresses via /lists/allowedips file which is a single line per entry of ip address to allow
• blocking IP addresses via /lists/blockedips file which is a single line per entry of ip address to block
• allowing user agents via a /lists/allowedagents file which is a single line per entry of useragents or regex patterns to match against. These must be go based regular expressions.
• blocking user agents via a /lists/blockedagents file which is a single line per entry of useragents or regex patterns to match against. These must be go based regular expressions.

There are also annotations that can be added to specific ingress objects that allow for ip allowlist or specific user agent blocking.

• idling.amazee.io/ip-allow-list - a comma separated list of ip addresses to allow, will be checked against x-forward-for, but if true-client-ip is provided it will prefer this.
• idling.amazee.io/ip-block-list - a comma separated list of ip addresses to allow, will be checked against x-forward-for, but if true-client-ip is provided it will prefer this.
• idling.amazee.io/allowed-agents - a comma separated list of user agents or regex patterns to allow.
• idling.amazee.io/blocked-agents - a comma separated list of user agents or regex patterns to block.

Note: Providing the annotations overrides the global block list, it does not append.

Additionally, you can add annotations to a namespace to allow the interval checks within the namespace to be different to the globally applied intervals.

• idling.amazee.io/prometheus-interval - set this to the time interval for prometheus checks, the format must be in 30m|4h|1h30m notation
• idling.amazee.io/pod-interval - set this to the time interval for pod uptime checks, the format must be in 30m|4h|1h30m notation

Also requests can be forced to verify by using a javascript snippet in the unidling page to call back to aergia to prove that they are a user and not a bot or some other automated system. See the README on how to turn this feature on and also the annotation to disable this per namespace if required.

Using these features would allow a platform operator to restrict how environments are unidled.