Customizer: Add meta capability `customize` which is mapped to `edit_theme_options`.

You can now allow users to access the Customizer, say for any user who can `edit_posts`, via `map_meta_cap` or `user_has_cap` filter. See ticket for examples.

props westonruter, nacin.
fixes #28605.
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git-svn-id: http://core.svn.wordpress.org/trunk@28954 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove `plugin_install_details_link` filter, which was added in [29047].

see #28785.
Built from https://develop.svn.wordpress.org/trunk@29171


git-svn-id: http://core.svn.wordpress.org/trunk@28955 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix wrong indentation in [29136].
Built from https://develop.svn.wordpress.org/trunk@29172


git-svn-id: http://core.svn.wordpress.org/trunk@28956 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove unused variable in `WP_Theme_Install_List_Table::install_theme_info()`. Unused since [26380].

props Corphi.
fixes #28749.
Built from https://develop.svn.wordpress.org/trunk@29173


git-svn-id: http://core.svn.wordpress.org/trunk@28957 1a063a9b-81f0-0310-95a4-ce76da25c4cd