Integrate raw TRMF implementation into PyPOTS

[WenjieDu]

What does this PR do?

1. fixing Add TRMF #557 and add testing cases for TRMF;
2. updating docs;

Before submitting

• This PR is made to fix a typo or improve the docs (you can dismiss the other checks if this is the case).
• Was this discussed/approved via a GitHub issue? Please add a link to it if that's the case.
• I have commented my code, particularly in hard-to-understand areas.
• I have written necessary tests and already run them locally.

[coveralls]

Pull Request Test Coverage Report for Build 13194790769

Details

• 150 of 155 (96.77%) changed or added relevant lines in 8 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 84.419%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pypots/imputation/trmf/model.py	39	44	88.64%

Totals
Change from base Build 12015227701:	0.1%
Covered Lines:	12196
Relevant Lines:	14447

---

💛 - Coveralls