#971: Ability to run "migration script" on update

[alfeilex]

This PR implements the migration command which is executed after devon ide update scripts, for example. The script runs various migration scripts located in the folder DEVON_HOME/scripts/migrations.

Example:
The current IDE version is 2022.03.001 and the user updates the IDE to the latest version. So all migrations scripts > 2022.03.001 will be executed for the migration.

Related issue: #971

[hohwille]

@alfeilex Thanks for your PR. Looks already good to me. 👍
The spot where you integrated the change is fine.
We should discuss if migration should be a commandlet. The impact is that end-users will get this via code-completion and devon help while IMHO it is something internal not intended for end-users. So I would rather move this to the scripts folder out of command folder.
IMHO we should consider creating a documentation/migration.asciidoc file as well.

[hohwille]

I found a potential conflict of requirements:
#1032 suggests to change the output of devon -v and this PR is using it in order to determine the current version installed.
Maybe we can easily solve this when we address my review suggestion to maintain the version in ${DEVON_IDE_HOME}/.devon.software.version.

[hohwille]

@alfeilex Thanks for this PR. Looks quite good now 👍
Sorry, but I still have some last review comments for rework to make this fully functional.

[hohwille]

@alfeilex Thanks for the update 👍
Ready for merge now.