feat: add trial_columns to EventDataFrame

[dkrako]

Description

For trializing the event detection method it is nice to have info on the trial columns available in the EventDataFrame class itself.

Implemented changes

• [x] add trials argument for passing a list of trial identifiers
• [x] add trial_columns for passing a list of columns that refer to trial identifiers
• [x] enforce trial columns to be at the start of the dataframe

Type of change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• [x] test for correct trial column names
• [x] test for correct trial identifier data

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] I have checked my code and corrected any misspellings

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (8ac7530) 100.00% compared to head (b2a7ba2) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #670 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 54 54 Lines 2374 2386 +12 Branches 594 597 +3 ========================================= + Hits 2374 2386 +12 ```

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