Finalize PA copy

[macfarlandian]

What needs to be done? Why does it need to be done?
Includes an introductory blurb for the homepage plus any edits that may be requested internally or externally.

Additional context
n/a

[hobuobi]

Drafting final copy here! Summarizing the biggest changes:

• Added copy for the landing page (largely taken from the PADOC mission statement).
• Need to investigate the prominence of new admissions -- the current copy presumes that new admissions are a smaller proportion of total admissions.
• Might want to add some context on why the prison population has grown and shrunk (mandatory minimums, covid, etc)