CSHARP-5453: Add builder for CSFLE schemas

[papafe]

No description provided.

[papafe]

@sanych-sun @damieng Can you give a look at the current state of the API? It's mostly functioning too, but I would like to get some feedback before writing tests.
Some notes:

• At the moment the naming is derived from the name the fields have in the json schema, as presented in the documentation(here and here).
• I taken examples mostly from the documentation pages, with some differences regarding the keyId.
• I'll take care of the xml docs only at the end.

[papafe]

@sanych-sun @damieng A couple of notes for the review:

• I have decided to reuse EncryptionAlgorithm and not create a new enum, even though EncryptionAlgorithm contains some values that are not valid for the schema, but will throw an exception.
• bsonType is actually optional, differently from what we discussed together. For this reason I slightly modified the overloads to avoid ambiguities when calling the methods.
• The whole encrypt section of a field could be empty. This is supported in the PR

[damieng]

LGTM

[sanych-sun]

LGTM

[papafe]

@damieng @sanych-sun I know you've already LGMTd this, but I've added added a method to convert BsonType to its string representation to our public API as was also requested by @damieng.
Just wanted to have a check if the naming makes sense, and if we should keep it as an extension method, or we prefer to have it as a static method on BsonUtils, for instance.

[papafe]

@rstam this is the new method

[rstam]

I'm not sure we should add this to the public API just so EF Core can use it. EF Core can easily duplicate this very small method.

Unless there is a clear scenario where a USER would find this useful, I wouldn't add it to the public API.

Definitely a good idea to centralize this conversion in an internal method for our own consumption.

If we do make this public I suggest it be done as a separate JIRA ticket so that users can see it.

[damieng]

It's a useful method with a clear and defined purpose and limited API surface. If I need it in the EF provider chances are other people need it too and probably also had to reproduce it. They'd need it right now if they're doing their own queryable encryption or CSFLE work and are trying to leverage BsonType in order to generate the schema.

[rstam]

I'm not sure we should add this to the public API just so EF Core can use it. EF Core can easily duplicate this very small method.

Unless there is a clear scenario where a USER would find this useful, I wouldn't add it to the public API.

Definitely a good idea to centralize this conversion in an internal method for our own consumption.

If we do make this public I suggest it be done as a separate JIRA ticket so that users can see it.