MDL-40595 tool_behat: Referencing init.php script

Almost everybody will use init.php instead of
running manually the composer commands and util.php
to install and enable the test environment.
MDL-40315 behat: Performance improvement

We look for exceptions after each step, this patch
includes a pre-checking query to avoid multiple queries
for each step when most of the time they are not necessary.
MDL-39695 theme_formal_white: added a colour hover for coursebox following trendcolour setting
MDL-39770 mod_chat: some tweaks to make it prettier to reduce screen wastage
MDL-39770 mod_chat: cleanup of the Bubble chat theme
MDL-40585 backup: cache XML parent paths

For $this->groupedpaths, using a key is faster as there is
no need to do in_array searches.

Parent cache allows dirname calls to be substantially reduced.
2048 was chosen as a cache size as this class operates on chunks
of the restore at a time, 8k questions produces a parent cache of
about 500 paths and uses 300K of memory.  Scaling up to 2048 will
use about 1.2M of RAM for really large restores.  This is acceptable
for the 48% function call reduction and the 10% runtime improvement
seen.
MDL-40584 backup: Query db once per category in precheck

The cache is function local and testing against a large database
indicates 10k questions is a large category.  Restore already
uses MEMORY_EXTRA and that will have enough space for the couple
of megabtyes a local sql hash will introduce.
MDL-40670 Theme: Rescale headings overriding bootstrap defaults
MDL-40121 Added plugin format_singleactivity
MDL-40121 Support old activities with subtypes
MDL-40121 Added format_singleactivity in standard package
MDL-40680 store_memcached: fix serialiser options

* Use correct lang string for SERIALIZER_IGBINARY
* Use PARAM_INT for the parameter
MDL-40666 cohort: remove duplicated code from tests
MDL-40666 enrol|cohort: PARAM_NUMBER -> PARAM_INT

PARAM_NUMBER is a float, our id's are int's

* Fix core_cohort_get_cohorts to specify correct return type on cohort id
* Fix core_enrol_get_enrolled_users_with_capability to specify correct
  correct return type on user id
* Fix core_cohort_update_cohorts to specify the right parameter type
  (int) on cohort id
* Add tests to verify the bug on core_cohort_update_cohorts param type.
MDL-37333 theme: Fix 'Clear theme caches' redirect.
MDL-38837 badges: Check for http or https in badges backpack support
MDL-40295 wiki mod: fix set_url() error for printer friendly page.
Additionally, fix wiki pagelayout for printing
MDL-39441 behat: Restrict config.php allowed settings
MDL-39441 behat: New setting to expand the list of allowed settings
MDL-40589 - Theme/CLEAN - Flip YUI3 tree item icon in RTL mode in folder resource