Allow predefined functions in CI config interpolation; add truncate fxn

What does this MR do and why?

This MR adds support for functions to be specified in the Ci interpolation block. The syntax supported is:

$[[ <access> | <func1> | <func2> | ... <funcN> ]]

where <access> specifies the value to retrieve (e.g. inputs.key) and funcX are optional functions that you can provide with or without arguments.

The truncate(<offset>,<length>) function was also created so that it can be used to test this implementation.

Resolves #409462 (closed) (Step 1) as well as Step 3 (#409462 (closed)).

How to set up and validate locally

1. Enable the FF: Feature.enable(:ci_include_components).
2. Create a component file with the following contents:

components/component-1/template.yml

spec:
  inputs:
    test:
      default: 012345678
---
test-job-1:
    script: echo $[[ inputs.test | truncate(1,3) ]]

3. In the Pipeline editor, update the config with the following. (Adjust the component path as needed.)

include:
  - component: gdk.test:3000/group-a/project-6/components/component-1@master

4. Observe that the Full configuration shows the input value truncated to 3 letters and offset by 1:

5. You can also test the following scenarios:

Component	Expected Result
Multiple functions: $[[ inputs.test | truncate(1, 7) | truncate(2,3) ]]
Too many functions: $[[ inputs.test |f|f|f|f|f|f|f|f|f|f|f|f|f|f|f
String values (they get converted to 0 value integer in the truncate function): $[[ inputs.test | truncate("foo","bar") ]]
Too many arguments: $[[ inputs.test | truncate(1,3,5) ]]
Too few arguments: $[[ inputs.test | truncate(3) ]]
Invalid function pattern: $[[ inputs.test | truncate%(1,3) ]]
Unknown function: $[[ inputs.test | undefined(1,3) ]]
Multiple interpolation blocks: $[[ inputs.test | truncate(1, 7) | truncate(2,3) ]] and $[[ inputs.test | truncate(2,3) ]]

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #409462 (closed)