Refactor package install instructions to use state and getters

What does this MR do?

This MR is the start of the refactoring proposed in #201730 (closed). It concentrates on:

• Changing app.vue from using props to state
• Adds Vuex getters for generating the instruction strings
• Updating the conan, maven and nuget installation components to use Vuex and the new getters
• Updating the tests for each component to support the refactoring
• Update the install components to use gl-sprintf

It does not cover:

• Changing i18n strings to use the new gl-sprintf component I buckled and did this in the end.
• Refactoring the npm_installation component. This is a little more complicated and might need backend so will be covered in a dedicated MR
• Combining installation components or changing their rendering logic

This is the first stage of refactoring and more MR's will come with further improvements. This MR is already quite big, so I wanted to focus specifically on the points above.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team