feat: Add plugin for OpenTofu

[chenzejun]

Standards checklist:

• The PR title is descriptive.
• The PR doesn't replicate another PR which is already open.
• I have read the contribution guide and followed all the instructions.
• The code follows the code style guide detailed in the wiki.
• The code is mine or it's from somewhere with an MIT-compatible license.
• The code is efficient, to the best of my ability, and does not waste computer resources.
• The code is stable and I have tested it myself, to the best of my abilities.
• If the code introduces new aliases, I provide a valid use case for all plugin users down below.

Changes:

Add plugin for OpenTofu which is a fork of Terraform that is open-source, community-driven

Migrate completion ability form Terraform plugin with some update for Opentofu, such as descrptions
Use different alias from Terraform plugin to avoid conflict(alias tt='tofu' vs. alias tf='terraform')
Add three useful alias for refresh(alias ttr='tofu refresh'), test(alias ttt='tofu test') and workspace(alias ttws='tofu workspace') command

Other comments:

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