Output RMSE map and time series for decay model fit

[tsalo]

Closes #861.

Changes proposed in this pull request:

• Add a function to calculate RMSE 4D time series from monoexponential model fit.
• Add RMSE mean brain and time series plots to the HTML report.
• Combine RMSE time series and global signal time series (when calculated) into a desc-confounds_timeseries.tsv file. This removes the global signal time series file (desc-globalSignal_timeseries.tsv).

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 94.25287% with 5 lines in your changes missing coverage. Please review.

Project coverage is 89.91%. Comparing base (af5e99a) to head (730354a). Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
tedana/decay.py	93.33%	1 Missing and 1 partial :warning:
tedana/io.py	84.61%	1 Missing and 1 partial :warning:
tedana/workflows/tedana.py	80.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1044 +/- ## ========================================== + Coverage 89.80% 89.91% +0.11% ========================================== Files 26 26 Lines 3540 3621 +81 Branches 621 629 +8 ========================================== + Hits 3179 3256 +77 - Misses 212 214 +2 - Partials 149 151 +2 ```

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[tsalo]

@madisoth gave me the thumbs up on this offline, so I'm opening it up for review.

[tsalo]

Here's the mean RMSE image for the 3-echo dataset:

Here's the timeseries plot (with +/- 1 SD) for the same dataset:

[tsalo]

The results are now substantially different:

[handwerkerd]

The results are now substantially different:

I do expect the values to be non-trivially lower because you were including voxels with 1 good echo, which meant fit coefficients of 0 (i.e. the residual error would be the entire time series).

[tsalo]

Ah, okay. That's a relief then.

[tsalo]

That's fixed in my most recent commit.

[tsalo]

@handwerkerd I think everything should be good now. Would you mind taking another look?

[tsalo]

Thanks @handwerkerd!

Here's what the updated 3-echo timeseries plot looks like, for posterity.