Squad

This 1.27 release starts using external storage for test
run files as a step prior to remove them from DB. Next releases
will come accordingly.

The release also works around a bug with LAVA REST responses
that don't always include the unit of a metric.

Lastly, this release adds a new model called `PluginScratch`, to be
used by plugins whenever extra database storage is required. Plugins
should clean up their data after work is finished.

Complete list of changes going in:

* ci: work around LAVA REST error
* commands: migrate_attachments: avoid OOM errors
* core:
* add PluginScratch object
* delay notification if there are PluginScratch-es
* migrate_attachments: reduce number of threads
* start using storage
* doc:
* conf: turn off magic quotes
* plugins: make gerrit configuration yaml code
* fix curl calls in plugins page
* plugins: gerrit: use same regex for split and match checks

This 1.26 marks a big change in SQUAD: it *completely removes
the name from Test models*. This field/column is the responsible
for half the size of DB and it might become an issue in setups
with hundreds of millions of tests.

This release also starts adapting SQUAD to use storage for TestRun
files (tests, metrics and logs) and Attachment. The next release
should start using these new fields and further releases will swap
to use storage fields only, thus saving lots of space in DB.

The release also fixes a timeout when viewing a build page, and a
timeout when acessing api for testrun/suite tests.

Lastly, this release makes Postgres an optional dependency for
SQUAD, which now should be installed as `pip install squad[postgres]`
if that RDBS is required, otherwise Sqlite will be used instead.

Complete list of changes going in:

* api: improve testrun/suite tests load times
* core:
* add FileField to Attachment to store contents
* add FileFields to store Testrun attachments
* add mgmt command for moving attachments out of DB
* allow Attachment.data to be null
* commands: add script to clean tradefed bad entries
* fix progress print in mgmt commands
* migrations: fix storage migrations
* models: increase size of password in PatchSource
* models: remove name column from Test
* dockerfile: add django-storages and boto3
* dockerfile: downgrade boto3
* frontend, views: fix suite parsing in test details
* frontend: views: avoid loading attachment data
* settings: define default location for storage
* setup: make postgres optional
* test: core: test storage fields

This 1.25.2 release fixes two bugs: first treats lava results' metadata
field as both string and yaml, the second bug hunt us down for a few months
triggering gerrit test exceptions at random, but it's fixed now.

Complete list of changes going in:

* ci: backend: lava: Parse results always expects metadata as a dict.
* core: utils: improve cryptographic functions

This 1.25.1 release fixes a bug that caused broken links to show
up in default notification templates.

Complete list of changes going in:

* core: templates: notification: Fix broken links

This 1.25 release adds a few major items:

* adds support of "unit" for metrics, but still preserves backwards compatibility
* api:
* standardizes API to use self discoverable url instead of id for all endpoints
* handles http errors as Json, instead of regular Django pages
* prepare squad to get test name column removed by making the field nullable
and stop using it
* adds option to disable sending emails to admins in setups that use other types of
notification, e.g. Sentry
* adds support for celery result backends, which allows celery to run group of tasks

Complete list of changes going in:

* api:
* rest: sandardize url-id in rest api
* http: handle 404 as json on api requests
* core:
* models: add unit field to Metric model
* models: add shortcut to get project settings
* migrations: "rebased" migration to make test name nullable
* models: use SuiteMetadata.name in favor of Test.name
* plugins:
* gerrit: add support to custom labels
* gerrit: allow multiple labels review
* settings:
* add celery result backend
* add option to turn off admin error emails
* fix SQUAD_SEND_ADMIN_ERROR_EMAIL flag values
* test: remove leftover print

This 1.24 release adds "tests" to suite endpoints, makes
test job endpoint a bit faster to load and fix the recently
added "Known Issues" project tab.

Complete list of changes going in:

* api: rest: defer definition from TestJob endpoint
* api: rest: add tests endpoint to suite view
* frontend: fix missing project nav in knownissues
* test: fix gerrit unit tests