Consistent labels

[sbreitbart-NOAA]

As per #163:

• Remove duplicated write_caption() function
• Update plotting functions to export rdas with filenames that match labels in caption_alt_text.csv
• Update topic_label in plotting functions so that it is created automatically as a reflection of the function title (in cases without a relative option)
• Update add_more_key_quants() as necessary
• Update/add tests

[github-actions]

New version checklist

• Package version in DESCRIPTION has been updated
• Release notes have been drafted/published
• Cheatsheet content has been updated (if applicable)
• Cheatsheet version has been updated

[github-actions]

Code Metrics Report

Coverage	Code to Test Ratio	Test Execution Time
71.1%	1:0.1	4m41s

Code coverage of files in pull request scope (85.0%)

Files	Coverage
R/plot_abundance_at_age.R	76.3%
R/plot_biomass.R	95.0%
R/plot_biomass_at_age.R	76.3%
R/plot_catch_comp.R	79.2%
R/plot_fishing_mortality.R	100.0%
R/plot_indices.R	83.3%
R/plot_landings.R	100.0%
R/plot_natural_mortality.R	79.6%
R/plot_recruitment.R	63.6%
R/plot_recruitment_deviations.R	71.9%
R/plot_spawning_biomass.R	78.9%
R/plot_stock_recruitment.R	97.6%
R/table_landings.R	95.1%
R/utils_rda.R	86.0%

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Reported by octocov

[Schiano-NOAA]

Looks great! I think this is a great improvement for the user and understandability and consistency of the package