Use ':root', rather than alias 'root' for default root collection

[ekraffmiller]

What this PR does / why we need it:

The root collection alias, 'root' is not a constant, it is an editable field in the Collection. So we need to use the special keyword ':root' to get the root collection. This affects all use cases that default to the root collection if no collectionId param is provided.

Which issue(s) this PR closes:

• Closes Support dynamic alias for the root collection #191

Related Dataverse PRs:

• Depends on #

Special notes for your reviewer:

Suggestions on how to test this:

Visual inspection of the code, including the updated Readme for the use cases, and review of the tests that use the default root collection.

Is there a release notes update needed for this change?:

Additional documentation:

[g-saracca]

This looks really good @ekraffmiller!
I suggested a commit (maybe is not needed) and have a doubt about this part of the code in collectionHelper.ts, should be use ':root' instead of 'root' also there?

export async function createCollectionViaApi(
  collectionAlias: string,
  parentCollectionAlias: string | undefined = undefined
): Promise<CollectionPayload> {
  try {
    if (parentCollectionAlias == undefined) {
      parentCollectionAlias = 'root'
    }

Another thing, just out of curiosity, do all API endpoints work with this special id ':root'?

[ekraffmiller]

Another thing, just out of curiosity, do all API endpoints work with this special id ':root'?

This looks really good @ekraffmiller! I suggested a commit (maybe is not needed) and have a doubt about this part of the code in collectionHelper.ts, should be use ':root' instead of 'root' also there?

export async function createCollectionViaApi(
  collectionAlias: string,
  parentCollectionAlias: string | undefined = undefined
): Promise<CollectionPayload> {
  try {
    if (parentCollectionAlias == undefined) {
      parentCollectionAlias = 'root'
    }

Another thing, just out of curiosity, do all API endpoints work with this special id ':root'?

Yes, it should be :root thanks!
All of the endpoints should work with this id, as far as I know. I left two use cases as is (not using :root). For 'publishCollection', the root collection should always be published, so I didn't think it needed it. For getCollectionItems, the API call doesn't require collectionId.

[ofahimIQSS]

Did visual inspection of code. Merging PR