This change makes it possible to access a parameter in templating, not
only to the top-level, i.e. the parameter itself, but also -- if the
parameter is of type "object" -- to access properties of the object
value. For example:

```yaml
parameters:
  - name: foo
    type: object
    default:
      a: 1
      b: 2

install:
  mymixin:
    some_property: ${ bundle.parameters.foo.a }
```

In this case, the `.a` was not possible before as `foo` was merely a
JSON string at the point of template resolution.

Signed-off-by: Leo Bergnéhr <[email protected]>

When trating object parameters as `map`s, the interpolation of the
object itself changes to the string representation of `map` instead of
the previous JSON string representation.

In order to keep the old behaviour of interpolating the object parameter
to a JSON string, this change introduces a new type, `FormattedObject`,
which implements the [`fmt.Formatter`](https://pkg.go.dev/fmt#Formatter)
interface. The implemented `Format` function turns the object's string
representation into a JSON string, instad of the default Go
representation of a `map`.

Example:

```yaml
parameter:
  - name: foo
    type: object
    default:
      bar: 1

install:
  mymixin:
    # Interpolating a nested property of the object parameter.
    val: "${ bundle.parameter.foo.bar }" # -> `val: '1'`

    # Interpolating the object parameter directly.
    obj: "${ bundle.parameter.foo }"     # -> `obj: '{"bar":1}'`
```

A shortcoming of this implementation is that interpolating nested
properties which also are `map` types will result in the interpolated
value being the string representation of `map`.

Signed-off-by: Leo Bergnéhr <[email protected]>

Signed-off-by: Kim Christensen <[email protected]>

Fixes lint error `SA1006`.

Signed-off-by: Leo Bergnéhr <[email protected]>

This adds support for tracking object parameters as sensitive. However,
if interpolating sub-properties of an object in templating, those will
not get tracked as sensitive.

Signed-off-by: Leo Bergnéhr <[email protected]>