Update CI user priveledges to use least priveledge

[ashley-evans]

Description

Currently the CI users, created by the buzzword-ci-users.yml template, have full access to all of the AWS services that they require in order to create/update/delete resources in AWS.

These users do not require full access to these resources and enabling them to have full access isn't a security best practise. Therefore, the privileges for these users should be updated such that they are only granted the least priveledge to deploy the buzzword stack.

Acceptance Criteria

AC01

• Update buzzword-ci-users.yml to no longer grant full access to all the services for each of the buzzword CI users
• Update buzzword-ci-users.yml to grant least priveledge to the buzzword CI users

AC02

• Test, Validate, and Deploy jobs in the Validate and Deploy pipeline must still pass as previously