Improve blueprint support.

[mshima]

Notable changes:

• Add configs meta.
  This is the base to a common cli option/prompt/config load/derived properties.
  Should simplify blueprint custom configs (WIP).
• Option choices can be specified:

% jhipster --client-framework foo
jhipster --client-framework foo
error: option '--client-framework <value>' argument 'foo' is invalid. Allowed choices are angular, react, vue, no.

• Improve java templates structure to be reused at java blueprints.
• Normalize java templates structure so templates can be used in blueprints with less breakages
• Misc improvements to blueprint support.

Related to #23449 and jhipster/generator-jhipster-micronaut#290.

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