[WIP] Added ability to load Docker based platform extensions.

[RobertNorthard]

As a user I want to be able to load Docker based platform extensions.

Discussion Points I replaced the credentials manager AWS build parameter for two password parameters as if null when loading a Docker based platform extension a CredentialsNotFound Checked Java exception is thrown when attempting to inject the AWS credentials using the "Use secret text(s) or file(s)" build environment feature.

The JSON collection structure has now changed so that an "extension_type" key needs to be provided (sample Collections JSON)

Maybe it would be better to have a load platform job per extension type to deal with the variance in parameters?

This depends on the following PR: Accenture/adop-nginx#22

[RobertNorthard]

As dicussed with @nickdgriffin @dsingh07 this pull request will be broken down.

Note:

• It is now a single repository per type of platform extension type, therefore an extension type variable is no longer required.

Tasks

• [x] Update cartridge specification to define PLATFORM_EXTENSION_TYPE env variable in metadata. PR adop-platform-extension-specification#2
• [x] Create dummy username and password credential to use as a placeholder for build credential params to avoid CredentialsNotFound Checked Java exception if not using an AWS platform extension type. PR Accenture/adop-platform-managment#21
• [x] Update adop-nginx to support extending the existing tools vhost PR Accenture/adop-nginx#22
• [x] Update Load_Platform_Extension jenkins job in adop-platform-management to support the docker platform extension type. PR Accenture/adop-platform-managment#22
• [x] Update Load_Platform_Extension_Collections to default AWS credentials to adop-default placeholder credentials PR Accenture/adop-platform-managment#22

[RobertNorthard]

Closing in favor of individual pull requests.