Allow to send metrics to a zabbix server

JIRA INFRA-614 #action In Progress

session._changes can be None in after_commit
See https://sentry.esss.lu.se/sentry/csentry/issues/63

JIRA INFRA-613 #action In Progress

IndexError raised due to:
{'cn': 'Alessio Curri (new)', 'sAMAccountName': 'alessiocurri2', 'mail': []}

JIRA INFRA-610 #action In Progress

LDAPInvalidFilterError: malformed filter raised due to the search filter
'(&(member=CN=Alessio Curri (new),OU=Contractors,OU=ESS
Users,DC=esss,DC=lu,DC=se))'

The brackets must be encoded using escape_filter_chars() to follow
RFC4515.
See https://github.com/cannatag/ldap3/issues/153

JIRA INFRA-550 #action In Progress

JIRA INFRA-576 #action In Progress

JIRA INFRA-576

This saves the state of hosts and items tables (search input,
ordering, paging position) so that it can be restored when the user
reloads a page.

See https://datatables.net/examples/basic_init/state_save.html

JIRA INFRA-608 #action In Progress

- switch to server side processing to retrieve network hosts
  (the table started to be bigger and takes time to load)
- add full text search using elasticsearch

Note that only the first IP is displayed in the host table (all
interfaces were displayed before). Search can be performed on any
interfaces.

JIRA INFRA-595 #action In Progress

1. If there is a rollback, some objects could be updated in the
elasticsearch index but not in the database.
Updating the index after commit ensures this can't happen.

2. In after_flush, not all relationships are updated properly. We need
to retrieve the objects in the after_flush_postexec event.
It can't be done in the after_commit event because we can't emit SQL at
that point.

See https://groups.google.com/forum/#!topic/sqlalchemy/GdB5J8h7YEU

JIRA INFRA-595

Decrease the number of SELECT calls by loading relationships that are
almost always used.

See https://docs.sqlalchemy.org/en/latest/orm/loading_relationships.html

JIRA INFRA-595

This is to ensure that when editing an object it is properly
re-indexed.

JIRA INFRA-575

JIRA INFRA-575

JIRA INFRA-575

Version shall be identical to the one used in production: 6.4.2

JIRA INFRA-575 #action In Progress

JIRA INFRA-575

The buttons should only be created if the items_table exists

JIRA INFRA-584

A deferred task will remain deferred forever if the task it depends on
fails. When checking for waiting tasks, we should ignore deferred tasks
that are too old.
"Too old" is currently set to 30 minutes. We shouldn't have tasks that
take that long. We might want to shorten that even a bit (to not block
new identical tasks to be run) but if a task failed there is probably
something to be done.

JIRA INFRA-559 #action In Progress

JIRA INFRA-569 #action In Progress

Add endpoints:
DELETE /network/hosts/<host_id>
DELETE /network/interfaces/<interface_id>

JIRA INFRA-570 #action In Progress

- set cascade to all and delete-orphan to delete interfaces when
  deleting a host
- button added on the view host page to delete host (admin only)

JIRA INFRA-557 #action In Progress

Retrieving all items from the database takes some time.
The task is thus handled by the RQ worker.
We use ajax to periodically monitor the status of the job
and redirect to the file when ready.
A progress bar is displayed to let the user see the progress.

The mechanism put in place could be re-used for other use cases.

JIRA INFRA-545 #action In Progress

JIRA INFRA-545

Included libraries:
- DataTables 1.10.18 (with bootstrap 4 theme)
- Buttons 1.5.2
- Column visibility 1.5.2
- Print view 1.5.2

JIRA INFRA-545

This was just a typo...
It should be AnsibleGroup instead of AnsibleQuery...

JIRA INFRA-548

ztp_stack can be empty.
We pass it as extra vars only if it's not.
The survey of the AWX_ZTP_CONFIGURATION template shall be updated to set
the ztp_stack parameter as not required.

JIRA INFRA-547

Allow to copy/paste the output of the "ansible-vault encrypt_string"
command to CSEntry

JIRA INFRA-544 #action In Progress

This is not directly supported by CodeMirror.
See https://github.com/codemirror/CodeMirror/issues/850

Add cm-resize library from https://github.com/Sphinxxxx/cm-resize

JIRA INFRA-543 #action In Progress

JIRA INFRA-526

The .git directory is used to identify the release number

WARNING! To pass the SECRET_KEY as en env variable, you should use
base64 encoding as the key is supposed to be a random string of bytes.

Errors are now sent to sentry.
No need to send them directly via e-mail.

JIRA INFRA-525

JIRA INFRA-525 #action In Progress

CSENTRY_ENVIRONMENT shall be set to production|staging|development
It can be used when sending errors to Sentry

JIRA INFRA-525