Audit permissions set by Dockerfile

[jonoliver]

Revisit the need for the chown and chmod commands here:

sparkpress-wordpress-starter/Dockerfile

Lines 31 to 34 in 43639f8

	# So we can update plugins
	RUN chown -R www-data:www-data /var/www
	RUN find /var/www/ -type d -exec chmod 0755 {} \;
	RUN find /var/www/ -type f -exec chmod 644 {} \;

• These steps can take quite a while when building the image, and the find commands appear to be overly broad.
• The comment only states so we can update plugins, but it's unclear what the initial issue was.

Can these lines be removed or modified?