Replace onobard.js with own connection logic

[enemycnt]

Description

Related Issue Or Context

Closes: #221

How Has This Been Tested? Testing details.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Checklist:

• I have commented my code, particularly in hard-to-understand areas.
• I have ensured that all acceptance criteria (or expected behavior) from issue are met
• I have updated the documentation locally and in chainbridge-docs.
• I have added tests to cover my changes.
• I have ensured that all the checks are passing and green, I've signed the CLA bot

[render]

Your Render PR Server URL is https://chainbridge-pr-231.onrender.com.

Follow its progress at https://dashboard.render.com/static/srv-c92cumk41ls93t1gu150.

[lgtm-com]

This pull request introduces 22 alerts when merging 6a6260e into 4dcee31 - view on LGTM.com

new alerts:

• 22 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 20 alerts when merging 6e31809 into 4dcee31 - view on LGTM.com

new alerts:

• 20 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 19 alerts when merging 52672a6 into 4dcee31 - view on LGTM.com

new alerts:

• 19 for Unused variable, import, function or class

[lgtm-com]

This pull request introduces 17 alerts when merging de9bcaa into 4dcee31 - view on LGTM.com

new alerts:

• 17 for Unused variable, import, function or class

[wainola]

Just one tiny comment

[wainola]

can we get rid of this commented line?

[lgtm-com]

This pull request introduces 17 alerts when merging a2ae4d5 into 4dcee31 - view on LGTM.com

new alerts:

• 17 for Unused variable, import, function or class