implement composer autoloader

[ell-ska]

currently running the phpcs command will show warnings like this for some of the /components/ files:

 1 | WARNING | A file should declare new symbols (classes, functions, constants, etc.) and cause no other side effects, or it
   |         | should execute logic with side effects, but should not do both. The first symbol is defined on line 7 and the first
   |         | side effect is on line 5.

from my research and understanding the issue is that BaseComponent uses require to render the component, which is considered a side effect. the suggested solution is to set up autoloading of files with Composer. i tried to do this (one attempt is still in refactor-namespace) but was unsuccessful. since i think this is a bit out of scope for the assignment i don't want to spend more time on this but i want to note that i'm aware of the issue!