Investments update

[entantoencuanto]

✌️ What does this PR do?

This PR adds the changes required to display the investments projects for Mataró with the most recent requirements:

Filters

• Filters accept allowedValues to restrict the options offered, and hideDropdown to render them always expanded
• Mataró: remove date, any-estat and import filters; add any-pla-inversions, zones and consells-territorials

Project detail tables

• Custom field plugins can declare vocabulary_ids in their configuration, and the API returns those vocabularies' terms in the metadata
• Tables now render a header row, resolve vocabulary columns to term names, and size each column by type (date / vocabulary / money / text)
• Mataró: new work start/end dates and -ambiva amounts including taxes with -ambiva suffix, partida replaced by the estats table, wider label column

Phases

• Support 8 phases with a proper gradient (negative styling from the 5th onwards)

API

• Admin terms API accepts external_id when creating terms

Refactor and fixes

• CustomField vocabulary methods decoupled: requires_vocabulary? (declared need) vs has_vocabulary? (declared or configured), vocabulary_ids always returns an array, and vocabularies covers both the single and the plugin-configured ones
• vocabulary_terms serialization reduced to a single pass, no longer dropping plugin-configured vocabularies

🔍 How should this be manually tested?

👀 Screenshots

Before this PR

After this PR

Does this PR changes any configuration file?

• new environment variable in .env.example?
• new entry in config/application.yml?
• new entry in config/secrets.yml?

(Changes in these files might need to update the role in Ansible)

📖 Does this PR require updating the documentation?

• new site configuration variable?
• new site template?
• new module/submodule settings?
• significant changes in some feature?