Add "./dspace database skip" command to optionally skip older migrations

[tdonohue]

References

Several users have encountered issues with older, ignored 5.7.* migrations (specifically 5.7.2017.04.11 and 5.7.2017.05.05) when running the ./dspace database migrate ignored command to upgrade from 6.x to 7.x.

• See this thread on dspace-tech
• Also see fix migration problem from 6.1 to 7.0 #8582 (This PR could be considered a replacement for fix migration problem from 6.1 to 7.0 #8582)

Description

Adds the ./dspace database skip [version] command, which allows you to skip applying a single ("Pending" or "Ignored") migration. Behind the scenes, this command tells Flyway that the skipped migration has already been run. Therefore, once a migration is skipped, it will not be run again in the future.

This PR looks larger than it really is, as I also refactored DatabaseUtils.main() to use a switch instead of a series of if/else if statements -- this makes the code much more readable. But, git seems to think I modified most of the main() method, when I've just realigned code to fit within the switch / case statements.

Instructions for Reviewers

1. The easiest way to test this new ./dspace database skip [version] command is to find a database which has not run either the 5.7.2017.04.11 or 5.7.2017.05.05 migrations.
   • I found an older 6.0-ish database dump which has not run either of these migrations & uploaded it to https://github.com/DSpace-Labs/AIP-Files/releases/download/demo-site-aips/dspace6_0-dbdump.sql This can be used to create a DSpace 6.x database which has not run these 5.7 migrations
2. Use ./dspace database info to verify one (or both) of the 5.7 migrations appear in the "Ignored" state.
3. Attempt to run ./dspace database migrate ignored on the database to upgrade to 7.x. You will receive errors for both the 5.7.2017.04.11 or 5.7.2017.05.05 migrations. Both of these migrations are no longer valid in 7.x, and are considered obsolete.
4. Run the ./dspace database skip [version] command to skip each 5.7 migration:

./dspace database skip "5.7.2017.04.11"
./dspace database skip "5.7.2017.05.05"

5. Using ./dspace database info again, verify that both of these migrations are now set to "Out Of Order" state (which means they are considered successfully run, but run out of numerical order)
6. Try the migration again: ./dspace database migrate ignored. This time, it will succeed.

I've tested this entire scenario using the example database above. I've verified it allows users to get past these failing, ignored migrations.

[corrad82-4s]

Hi @tdonohue , I have been able to test this PR and all run as expected and described. No remarks from my side

[tdonohue]

Merging with 1 Approval. I've added documentation for ./dspace database skip to both https://wiki.lyrasis.org/display/DSDOC7x/Database+Utilities and https://wiki.lyrasis.org/display/DSDOC7x/Upgrading+DSpace#UpgradingDSpace-Databasemigrateerrors:%22MigrationV5.7_2017.04.11__DS-3563_Index_metadatavalue_resource_type_id_column.sqlfailed%22or%22MigrationV5.7_2017.05.05__DS-3431.sqlfailed%22