Limit container scope to single schema

[MichalLytek]

Right now, the only way to register a 3rd party DI container is by using the global useContainer function. But this global way force us to share the same container between multiple buildSchema calls and multiple schemas will call in runtime the same container.

This PR change this API and make the container to be passed as the buildSchema option:

import { Container } from "typedi"
import { buildSchema } from "type-graphql"

await buildSchema({
  resolvers,
  container: Container,
});

It is placed in build context like the rest of the buildSchema options.

This PR will allow to move toward #110 and multiple schemas support without any leaks between them.

[codecov]

Codecov Report

Merging #241 into master will increase coverage by 0.29%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #241      +/-   ##
==========================================
+ Coverage   95.58%   95.88%   +0.29%     
==========================================
  Files          67       67              
  Lines        1064     1044      -20     
  Branches      187      183       -4     
==========================================
- Hits         1017     1001      -16     
+ Misses         46       42       -4     
  Partials        1        1

Impacted Files	Coverage Δ
src/utils/index.ts	100% <ø> (ø)	⬆️
src/resolvers/create.ts	100% <100%> (ø)	⬆️
src/utils/container.ts	100% <100%> (+10.52%)	⬆️
src/resolvers/helpers.ts	100% <100%> (ø)	⬆️
src/schema/build-context.ts	100% <100%> (ø)	⬆️

---

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 90d55a8...3ecbf5b. Read the comment docs.