mri_protocol table's ScannerID is set to 0 in RaisinBread and not nullable

[cmadjar]

The ScannerID field of the mri_protocol table has been modified to add a foreign key constraint with the ID field of the mri_scanner table.

Historically, we used to set the ScannerID field of the mri_protocol table to 0 when a protocol is valid on all study's scanners. Instead of setting the ScannerID field to 0 when an MRI protocol should be valid across all scanners, we should allow for NULL values in the ScannerID field of the mri_protocol table.

TODOs:

• modify the schema here to allow for NULL values:

  Loris/SQL/0000-00-00-schema.sql

  Line 623 in 12041ad

  `ScannerID` int(10) unsigned NOT NULL default '0',

• create a patch that will alter the mri_protocol table in https://github.com/aces/Loris/tree/main/SQL/New_patches so that existing LORIS instances can update their mri_protocol table
• modify the LORIS-MRI code to reflect the change: Default ScannerID should be NULL instead of 0 in mri_protocol when a protocol is valid on all scanners Loris-MRI#637
• modify RaisinBread SQL statements to set ScannerID of the mri_protocol table to NULL instead of 0 in the following file: https://github.com/aces/Loris/blob/main/raisinbread/RB_files/RB_mri_protocol.sql
• modify the CHANGELOG.md file with the changes for @ridz1208 :)