Removed all use of the DB for serving/caching the theme from style.php,
acp_style no longer stores the theme modified time either.
As a consequence currently all stylesheets will be served through style.php
(with no caching) until imagesets are removed [PHPBB3-10336], then
they can we served as static files by HTTPd.
PHPBB3-9741
The bulk of database storage of templates is removed, rendering template
stored in the database as useless.
Theme database storage is reduced to a skeleton for full removal soon.
This commit was cherry picked from the old feature/ascraeus-experiment branch
the old commit hash is 0dbe7e3b6cd450342d3c566eb2caf36ca1b5db8e.
PHPBB3-9741
* develop-olympus:
[ticket/10370] Add function documentation for get_stacktrace().
[ticket/10370] Explain that we are not the ones hiding backtrace pieces.
[ticket/10370] Call htmlspecialchars() after phpbb_filter_root_path().
[ticket/10370] Add require_once to whitelisted functions.
[ticket/10370] Use single string instead of an array for arguments.
[ticket/10370] Ease up code checking for arguments of include etc.
[ticket/10370] Use unset() on the first backtrace instead of checking in loop.
[ticket/10370] Use phpbb_filter_root_path() in get_backtrace().
* github-bantu/ticket/10370:
[ticket/10370] Add function documentation for get_stacktrace().
[ticket/10370] Explain that we are not the ones hiding backtrace pieces.
[ticket/10370] Call htmlspecialchars() after phpbb_filter_root_path().
[ticket/10370] Add require_once to whitelisted functions.
[ticket/10370] Use single string instead of an array for arguments.
[ticket/10370] Ease up code checking for arguments of include etc.
[ticket/10370] Use unset() on the first backtrace instead of checking in loop.
[ticket/10370] Use phpbb_filter_root_path() in get_backtrace().
* develop-olympus:
[ticket/10369] Replace root path with "[ROOT]" as per IRC.
[ticket/10369] Add warning about paths outside of phpBB root not being filtered
[ticket/10369] Rename filter_errfile() to filter_root_path().
[ticket/10369] DRY code to remove phpbb path from errfile.
[ticket/10369] Always include errfile and errline in format_errors().
* github-bantu/ticket/10369:
[ticket/10369] Replace root path with "[ROOT]" as per IRC.
[ticket/10369] Add warning about paths outside of phpBB root not being filtered
[ticket/10369] Rename filter_errfile() to filter_root_path().
[ticket/10369] DRY code to remove phpbb path from errfile.
[ticket/10369] Always include errfile and errline in format_errors().
* github-noxwizard/ticket/10322:
[ticket/10322] Separate template varref resolution from output generation
[ticket/10322] Dynamic template include test
[ticket/10322] Fix dynamic template includes
Most template variables can now have their PHP variable name resolved instead
of only compiling directly. This allows for the use of block vars in INCLUDE
statements. This does not work for language variables since they require
multiple checks. Added tests for the new types of allowed INCLUDEs.
PHPBB3-10322
