API `Verification.Spotify` module from prototype

[w0rd-driven]

There's likely a better name for this but it likely involves wiring up SpotifyEx and making the appropriate calls.

• [x] Configure the dependency following https://github.com/jsncmgs1/spotify_ex_test
• [x] Search for the artist to get the id. Is there a better way?
• [x] Search for albums by artist.

Upserts should capture new records but it may be safer to do queries to filter out existing albums. I could do something like "Get all album names for this artist. Enum.filter where name NOT in list."

[w0rd-driven]

A new issue should add a migration for a spotify_id as we likely don't need to get the artist id every call. I don't know if this changes though but I do know picking the artist can be problematic.

[w0rd-driven]

Debugging the library and how I authenticate with each request (this is fine but definitely overkill):

** (MatchError) no match of right hand side value: {:ok, %{"error" => %{"message" => "Only valid bearer authentication supported", "status" => 400}}}
    (beatseek 0.1.0) lib/beatseek/verification/spotify.ex:16: Beatseek.Verification.Spotify.get_artist/1
    (beatseek 0.1.0) lib/beatseek/verification/spotify.ex:8: Beatseek.Verification.Spotify.verify/1
    iex:1: (file)

If this happens it's usually because the credentials aren't found. System.get_env("SPOTIFY_CLIENT_ID") and System.get_env("SPOTIFY_CLIENT_SECRET") should both return the credentials configured in Spotify. What usually happens is Spotify.encoded_credentials() returns "Og==" instead of a longer base64 encoded string. This happens because Spotify in deps/spotify_ex/lib/spotify_ex.ex is looking for Application.get_env(:spotify_ex, :client_id) or compile time values. This is not easily apparent in the Phoenix 1.5 test app at https://github.com/jsncmgs1/spotify_ex_test.

For the trouble this is worth and the fact that I can't run Albums.get_artists_albums nor can I really customize the query to just be in the US market, I find the library really doesn't give me much. I could build the credentials piece in Req but this is honestly fine.

I had done this for a take-home project luckily because I ran into issues immediately. I have no clue where I got the code to do this either btw, but it just works when it does. I would've been so fucking lost without past me figuring this out a year ago. Way to go.