remove bids_id column from manifest (#161)

* remove `bids_id` column from manifest

* remove `bids_id` description

docs/nipoppy/configs.md

@@ -78,15 +78,14 @@ Nipoppy requires two global files for specifying local data/container paths and
       - `visit`: label to denote participant visit for data acquisition (e.g. `"baseline"`, `"m12"`, `"m24"` or `"V01"`, `"V02"` etc.)
       - `session`: alternative naming for visit - typically used for imaging data to comply with [BIDS standard](https://bids-specification.readthedocs.io/en/stable/02-common-principles.html)
       - `datatype`: a list of acquired imaging datatype as defined by [BIDS standard](https://bids-specification.readthedocs.io/en/stable/02-common-principles.html)
-      - `bids_id`: this is the `participant_id` after removing any non-alphanumeric character (e.g. "-" or "_") and attaching the `sub-` prefix. `participant_id` and `bids_id` in the manifest are used to link tabular and MRI data
    - New participant are appended upon recruitment as new rows
    - Participants with multiple visits (i.e. sessions) should be added as separate rows
 
 #### Sample `manifest.csv`
 
-| participant_id | visit | session | datatype                     | bids_id |
-|----------------|-------|---------|------------------------------|---------|
-| 001            | V01   | ses-01  | ["anat","dwi","fmap","func"] | sub-001 |
-| 001            | V02   | ses-02  | ["anat"]                     | sub-001 |
-| 002            | V01   | ses-01  | ["anat","dwi"]               | sub-002 |
-| 002            | V03   | ses-03  | ["anat","dwi"]               | sub-002 |
+| participant_id | visit | session | datatype                     |
+|----------------|-------|---------|------------------------------|
+| 001            | V01   | ses-01  | ["anat","dwi","fmap","func"] |
+| 001            | V02   | ses-02  | ["anat"]                     |
+| 002            | V01   | ses-01  | ["anat","dwi"]               |
+| 002            | V03   | ses-03  | ["anat","dwi"]               |