Lucas/t 231 timebox i can create a company at the same time im creating (#140)

This PR is a bit messy:

adding graphql schema
adding create company creation on company select on People page
some frontend refactoring to be continued

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Co-authored-by: Charles Bochet <charles@twenty.com>

server/src/api/graphql/enums/TransactionIsolationLevel.ts

@@ -0,0 +1,12 @@
+import * as TypeGraphQL from "type-graphql";
+
+export enum TransactionIsolationLevel {
+  ReadUncommitted = "ReadUncommitted",
+  ReadCommitted = "ReadCommitted",
+  RepeatableRead = "RepeatableRead",
+  Serializable = "Serializable"
+}
+TypeGraphQL.registerEnumType(TransactionIsolationLevel, {
+  name: "TransactionIsolationLevel",
+  description: undefined,
+});