Generate SObject type definitions for LWC

[vazexqi]

What does this PR do?

At a high level, this monitors the faux-classes for SObjects and generates the corresponding type definition for it. An example is shown below:

global class Order_Item__c {
    global List<AttachedContentDocument> AttachedContentDocuments;
    global List<Attachment> Attachments;
    global List<CombinedAttachment> CombinedAttachments;
    global List<ContentDocumentLink> ContentDocumentLinks;
    global User CreatedBy;
    global Id CreatedById;
...

generates

declare module "@salesforce/schema/Order_Item__c.CreatedBy" {
  const CreatedBy:any;
  export default CreatedBy;
}
declare module "@salesforce/schema/Order_Item__c.CreatedById" {
  const CreatedById:any;
  export default CreatedById;
}
declare module "@salesforce/schema/Order_Item__c.CreatedDate" {
  const CreatedDate:any;
  export default CreatedDate;
}
declare module "@salesforce/schema/Order_Item__c.Id" {
  const Id:any;
  export default Id;
}
...

Currently, we only generate the non-collection types (which translates to non-relationship types in SObject)

What issues does this PR fix or reference?

@W-4565889@

[codecov]

Codecov Report

Merging #589 into develop will decrease coverage by 0.58%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #589      +/-   ##
===========================================
- Coverage    72.68%   72.09%   -0.59%     
===========================================
  Files          155      155              
  Lines         6157     6157              
  Branches       953      953              
===========================================
- Hits          4475     4439      -36     
- Misses        1443     1485      +42     
+ Partials       239      233       -6

Impacted Files	Coverage Δ
...kages/salesforcedx-vscode-apex/src/requirements.ts	27.5% <0%> (-35%)	⬇️
...code-apex/src/views/readableApexTestRunExecutor.ts	0% <0%> (-27.78%)	⬇️
...s/salesforcedx-vscode-apex/src/views/testRunner.ts	0% <0%> (-23.41%)	⬇️
...ges/salesforcedx-vscode-apex/src/languageServer.ts	40.74% <0%> (-11.12%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d806cb9...f7c1cbf. Read the comment docs.