chore: Preparation for incoming static code analysis CI check

[paul1r]

What this PR does / why we need it:
This PR addresses a variety of issues found with GoSec in the Loki codebase.

Working with the security team, it was determined that these issues needed to be masked off via a comment, implying they had a thorough review, or fixed. Other less-important issues, such as not checking the return value of a function in an error path, are likely going to be fenced off at the scanner configuration level.

Notable changes include:

• Updating the bloom untar function
• Switching from MD5/SHA1 to SHA3 for hashing
• Changing the Loki canary to have a timeout
• Switching from math/rand to crypto/rand

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[CLAassistant]

All committers have signed the CLA.

[trevorwhitney]

This looks great, thanks Paul!