Set up manuscript-specific acknowledgements

[rando2]

Is your feature request related to a problem? Please describe.
Since some of the people in the acknowledgements contributed to specific sections, we may want to draft specific acknowledgements for each paper.

Describe the solution you'd like
@agitter suggested: We can write paper-specific acknowledgement text and show only the appropriate paragraph for each paper using template variables. However, we'd still have to write each paper-specific text block.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[agitter]

To elaborate on what I meant regarding template variables we could do something like this:

General acknowledgements text for all manuscripts.
{%- if individual is not defined or individual == "pathogenesis" %}
We thank X, Y, Z for these things in the pathogenesis manuscript.
{%- elif individual is not defined or individual == "evolution" %}
We thank X, Y, Z for these things in the evolution manuscript.
{% endif -%}

The idea is to lead with text that should appear in the merged manuscript and all individual manuscripts. Then any acknowledgements for a specific manuscript are shown in the merged manuscript and that individual manuscript.

[agitter]

Manuscript-specific acknowledgment text being used:

• Nutraceuticals Steps for Nutraceuticals Manuscript Submission #749 (comment)
• Therapeutics Steps for Therapeutics Manuscript Submission #738 (comment)