[ts/checkProjects] validate extends of all ts projects (#145176)

Fixes https://github.com/elastic/kibana/issues/145129

In order to make our TS setup in the repo far more efficient we needed
to make it a little more complicated than it used to be. This includes a
few rules that all tsconfig files need to follow which were currently
assumed to be true, but with this PR will now be validated:

1. No tsconfig.json files are allowed to extend the `tsconfig.json`
file. This file is used to produce types for the root of the repo, and
include the `package.json` file in a project so it can be referenced in
projects directly. Files which violate this rule were updated to point
to the root `tsconfig.base.json` file.
2. Every tsconfig.json file must extend the `tsconfig.base.json` file,
either directly or indirectly.

examples/field_formats_example/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.json",
+  "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "./target",
     "skipLibCheck": true