* hide action popover when scrolling data table

* flow

* add instance method for action hiding

Presto driver multi-aggregate and fixes

Refactor reference guide

fix typo in setup.clj

Unify test application db environment variables [ci drivers]

Rename functions with µ to microseconds [ci drivers]

Explicitly load driver code and fail tests when driver is present

* allow for auth specific admin setting 'subroutes'

* remove toggle

* add breadcrumbs

* better name for options component

* add tests

make create test async

add goBack utility

test click paths

The unicode character in the function name can cause problems with AOT
generated class names that have that µ in the filename. On some users
systems if this isn't encoded properly it can replace the µ with a ?
and cause failures compiling metabase.

Fixes #4441

Fixed driver installation description.

Integrated test infrastructure + an example test

This fixes a test failure in Vertica involving the date_trunc function
which expect timestamp strings to be explicitly cast as a timestamp.

Fixes #5085

Driver loading previously was very dependent on what code clojure
compiled first. If the Oracle driver was loaded before the plugin
directory was examined, it would result in the Oracle driver never
being loaded. This is due to clojure code only being loaded once when
required and the driver loading code being free floating code that is
only evaled when the namespace is loaded.

This commit switches that code to be in an -init-driver function that
is invoked when the driver is required. This ensures that regardless
of code loading order, the driver will be available if it's present.

This commit also includes code to fail the build if requested to test
on an engine when that engine's driver is not available. Previously if
you set ENGINES to "h2,oracle" but had no Oracle driver in the plugins
directory, the test would succeed, but only test against H2.

This unifies the code and the environment variables for specifying
test database connection parameters across all supported
databases. Existing databases that supported environment variables for
tests have been refactored to use the new environment variable
names. All of the connection environment variables are named similar
to:

MB_<DBNAME>_TEST_<PARAM>

For user on MySQL, the variable would be named:

MB_MYSQL_TEST_USER

Include fields metadata for Saved Questions 'virtual' DB