Update documentation with service accounts

[volodymyrZotov]

This PR updates documentation to mention Service Accounts support.

It also changes the term '1Password Connect Terraform Provider' to just '1Password Terraform Provider' to cover a wider scope of the tools that the Provider can work with (aka 1Password Connect and 1Password Service Accounts as per now).

Tasks:

• [x] Update autogenerated docs template templates/index.md.tmpl
• [x] Update bug report .github/ISSUE_TEMPLATE/bug_report.md

Improve CONTRIBUTE.md:

• [x] Add Sign Your Commits section.
• [x] Add Debugging section

Resolves #106

[volodymyrZotov]

@edif2008 thank you for the review. You're right it was done in #109, and that was merged to this branch, not to main. So nothing lost 🙂

We just split the work between me and @williamhpark and prepared this branch with all the documentation changes for the review.