Merge pull request #2018 from Guite/1.4

set random secret parameter on install and update
Merge pull request #2019 from Guite/1.4

merge custom parameters into main config, fixed #2003
Merge pull request #2020 from Guite/1.4

fixed mailer settings form wrt multiple credential field names, fixed #2016
Merge pull request #2021 from Guite/1.4

minor adjustments for test mailer output
Merge pull request #2022 from Guite/1.4

moved example module into own repository, fixed #1991
create own FatalErrorException and use
[README] Update link of user community site

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | none
| Refs tickets  | none
| License       | MIT
| Doc PR        | none

http://community.zikula.org/ not work, i change it to http://zikula.org/index.php/forum/
[Changelog] Update changelog

Merge changelog of https://github.com/zikula/core/blob/1.3.9/src/docs/CHANGELOG
Update link of community site
Merge pull request #2024 from pabloveintimilla/patch-7

[README] Update link of user community site
Merge pull request #2025 from pabloveintimilla/patch-9

[Changelog] Update changelog
change back to using base class for response
revert unrelated change
Merge pull request #2023 from craigh/FatalException

create own FatalErrorException and use
correct route name
correct route name
list only actually included files as combined in the output, fixed #1997