feat: add MQTT support

[badnikhil]

PR Description

this PR enhanced apidash by adding MQTT support

this just works ,doing my best to improve the code and align with expectations

Related Issues

#115

• Closes #115

Checklist

• [x] I have gone through the contributing guide
• [x] I have updated my branch and synced it with project main branch before making this PR
• [x] I am using the latest Flutter stable branch (run flutter upgrade and verify)
• [ ] I have run the tests (flutter test) and all tests are passing

Added/updated tests?

We encourage you to add relevant test cases.

• [ ] Yes
• [x] No, and this is why: will do later

OS on which you have developed and tested the feature?

• [ ] Windows
• [ ] macOS
• [x] Linux