Support fireworks-ai/llama-3-firefunction-v2

[ochafik]

fireworks-ai/llama-3-firefunction-v2 needs support for {%- filter trim -%}...{% endfilter %}, default & lower filters, array + concat

[ochafik]

Still needs work. Template expects functions & datetime variables in context, and these proved fiddly to resolve in minja which may indicate some other issue.