PLT-6965 jira integration (plus plugin scaffolding) (#6918)

* plugin scaffolding / jira integration

* add vendored testify packages

* webhook fix

* don't change i18n ids

* support configuration watching

* add basic jira plugin configuration to admin console

* fix eslint errors

* fix another eslint warning

* polish

* undo unintentional config.json commit >:(

* test fix

* add jira plugin diagnostics, remove dm support, add bot tag, generate web-safe secrets

* rebase, implement requested changes

* requested changes

* remove tests and minimize makefile change

* add missing license headers

* add missing comma

* remove bad line from Makefile

webapp/i18n/en.json

@@ -481,6 +481,7 @@
   "admin.integrations.custom": "Custom Integrations",
   "admin.integrations.external": "External Services",
   "admin.integrations.webrtc": "Mattermost WebRTC",
+  "admin.plugins.jira": "JIRA (Beta)",
   "admin.ldap.baseDesc": "The Base DN is the Distinguished Name of the location where Mattermost should start its search for users in the AD/LDAP tree.",
   "admin.ldap.baseEx": "E.g.: \"ou=Unit Name,dc=corp,dc=example,dc=com\"",
   "admin.ldap.baseTitle": "BaseDN:",
@@ -626,6 +627,18 @@
   "admin.password.requirementsDescription": "Character types required in a valid password.",
   "admin.password.symbol": "At least one symbol (e.g. \"~!@#$%^&*()\")",
   "admin.password.uppercase": "At least one uppercase letter",
+  "admin.plugins.jira.enabledLabel": "Enabled:",
+  "admin.plugins.jira.enabledDescription": "When true, you can configure JIRA webhooks to post message in Mattermost. To help combat phishing attacks, all posts are labelled by a BOT tag.",
+  "admin.plugins.jira.secretLabel": "Secret:",
+  "admin.plugins.jira.secretDescription": "This secret is used to authenticate to Mattermost.",
+  "admin.plugins.jira.secretRegenerateDescription": "Regenerates the secret for the webhook URL endpoint. Regenerating the secret invalidates your existing JIRA integrations.",
+  "admin.plugins.jira.userLabel": "User:",
+  "admin.plugins.jira.userDescription": "Select the username that this integration is attached to.",
+  "admin.plugins.jira.setupDescription": "Use this webhook URL to set up the JIRA integration. See {webhookDocsLink} to learn more.",
+  "admin.plugins.jira.webhookDocsLink": "documentation",
+  "admin.plugins.jira.secretParamPlaceholder": "secret",
+  "admin.plugins.jira.teamParamPlaceholder": "teamname",
+  "admin.plugins.jira.channelParamNamePlaceholder": "channelname",
   "admin.privacy.showEmailDescription": "When false, hides the email address of members from everyone except System Administrators.",
   "admin.privacy.showEmailTitle": "Show Email Address: ",
   "admin.privacy.showFullNameDescription": "When false, hides the full name of members from everyone except System Administrators. Username is shown in place of full name.",
@@ -832,6 +845,7 @@
   "admin.sidebar.general": "General",
   "admin.sidebar.gitlab": "GitLab",
   "admin.sidebar.integrations": "Integrations",
+  "admin.sidebar.jira": "JIRA (Beta)",
   "admin.sidebar.ldap": "AD/LDAP",
   "admin.sidebar.legalAndSupport": "Legal and Support",
   "admin.sidebar.license": "Edition and License",