chore: upgrade to Go 1.24 and update controller-gen

[tekenstam]

Description

This PR implements the updates described in issue #459 to upgrade the instance-manager project to Go 1.24.

Changes

• Updated Go version to 1.24 with toolchain go1.24.1 in go.mod
• Updated Dockerfile to use golang:1.24 as the base image
• Updated GitHub workflows to use Go 1.24
• Modified controller-gen installation process to use v0.14.0 for better compatibility with Go 1.24 and ARM architectures
• Reorganized GitHub issue templates to improve the contribution experience

Testing

• Verified project builds successfully with Go 1.24
• Generated manifests with the updated controller-gen version
• All tests are passing

Checklist

• I have updated relevant documentation
• I have added tests that prove my fix is effective or that my feature works
• I have signed my commits with git commit -s for DCO
• I have run make to ensure the codebase builds with my changes

Fixes #459

[shaoxt]

LGTM

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.99%. Comparing base (a31734e) to head (1e6e2fd).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #463      +/-   ##
==========================================
- Coverage   50.11%   44.99%   -5.13%     
==========================================
  Files          34       40       +6     
  Lines        6299     7017     +718     
==========================================
  Hits         3157     3157              
- Misses       2993     3711     +718     
  Partials      149      149              

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