Adapt wire-server charts so they can be used to run wire cloud

[akshaymankar]

charts/{brig,cargohol,galley,gundeck}: Allow not configuring AWS credentials and allow using a special service account.
This way, when operating wire in AWS cloud either instance profiles or IAM role attached to a service account can be used to communicate with AWS.

Allow new configurations in the brig chart:

• config.emailSMS.user.invitationUrl
• config.emailSMS.team.tInvitationUrl
• config.emailSMS.team.tActivationUrl
• config.emailSMS.team.tCreatorWelcomeUrl
• config.emailSMS.team.tMemberWelcomeUrl
• config.setProviderSearchFilter
• config.setWhitelist
• config.setFeatureFlags
• config.setCustomerExtensions

If any values in config.emailSMS.team are specified, all must be specified.

Allow new configurations in the gundeck chart:

• config.perNativePushConcurrency
• config.maxConcurrentNativePushes.soft
• config.maxConcurrentNativePushes.hard

Other changes:

• Default maxTeamSize changed from 500 to 10000. (larger teams have been supported by wire-server code for a while; but the default value had not been increased yet)

Checklist

• The PR Title explains the impact of the change.
• The PR description provides context as to why the change should occur and what the code contributes to that effect. This could also be a link to a JIRA ticket or a Github issue, if there is one.
• If this PR changes development workflow or dependencies, they have been A) automated and B) documented under docs/developer/. All efforts have been taken to minimize development setup breakage or slowdown for co-workers.
• If HTTP endpoint paths have been added or renamed, the endpoint / config-flag checklist (see Wire-employee only backend wiki page) has been followed.
• If a cassandra schema migration has been added, I ran make git-add-cassandra-schema to update the cassandra schema documentation.
• changelog.d contains the following bits of information (details):
  • A file with the changelog entry in one or more suitable sub-sections. The sub-sections are marked by directories inside changelog.d.
  • If new config options introduced: added usage description under docs/reference/config-options.md
  • If new config options introduced: recommended measures to be taken by on-premise instance operators.
  • If a cassandra schema migration is backwards incompatible (see also these docs), measures to be taken by on-premise instance operators are explained.
  • If a data migration (not schema migration) introduced: measures to be taken by on-premise instance operators.
  • If public end-points have been changed or added: does nginz need un upgrade?
  • If internal end-points have been added or changed: which services have to be deployed in a specific order?

[jschaul]

This iteration of helm chart changes is working, LGTM.

A changelog entry would be nice to add, though.

[jschaul]

CI seems to be failing though, still.

[jschaul]

Looks good, thanks for the detailed description!

[flokli]

s/cargohol/cargohold

small typo

[akshaymankar]

Fixed here: #2399