Use usernames where possible for system messages instead of display names

[Infinitay]

Chatterino currently uses a user's display name rather than their username when dealing with system messages. The following cases below are a few instances I noticed this happening:

• Raid/hosting messages
  
  
  "@badge-info=;badges=;color=;display-name=무한_시험;emotes=;flags=;historical=1;id=ed1edaed-78cc-4e81-8a62-9e77f1425fbf;login=callmeinfinity_v2;mod=0;msg-id=raid;msg-param-displayName=무한_시험;msg-param-login=callmeinfinity_v2;msg-param-profileImageURL=https://static-cdn.jtvnw.net/user-default-pictures-uv/215b7342-def9-11e9-9a66-784f43822e80-profile_image-70x70.png;msg-param-viewerCount=1;rm-received-ts=1659855317049;room-id=41070983;subscriber=0;system-msg=1\\sraiders\\sfrom\\s무한_시험\\shave\\sjoined!;tmi-sent-ts=1659855316922;user-id=120788097;user-type= :tmi.twitch.tv USERNOTICE #thekinkysoup",
• Gifted subs
  
  "@badge-info=;badges=;color=;display-name=토모로0117;emotes=;flags=;historical=1;id=1496b3b6-5e93-4979-bca1-07b9f8abccc5;login=viewer1245;mod=0;msg-id=subgift;msg-param-gift-months=1;msg-param-months=1;msg-param-origin-id=77\\s26\\s06\\sed\\sa6\\sb1\\sf5\\s8c\\s46\\s19\\sb0\\sc9\\s60\\se6\\s82\\sec\\s13\\sd2\\sd5\\s10;msg-param-recipient-display-name=_아톰;msg-param-recipient-id=189224322;msg-param-recipient-user-name=yxxjxxg;msg-param-sender-count=1;msg-param-sub-plan=1000;msg-param-sub-plan-name=뚜벅초;rm-received-ts=1659854921758;room-id=<room/broadcaterid>;subscriber=0;system-msg=토모로0117\\sgifted\\sa\\sTier\\s1\\ssub\\sto\\s_아톰!\\sThis\\sis\\stheir\\sfirst\\sGift\\sSub\\sin\\sthe\\schannel!;tmi-sent-ts=1659854921670;user-id=778394567;user-type= :tmi.twitch.tv USERNOTICE #<channelname>",
• Resubscriptions
  
  "@badge-info=subscriber/14;badges=subscriber/12,hype-train/2;color=#E4E724;display-name=현이씨;emotes=;flags=;historical=1;id=0325600e-8054-48ae-ba5c-2d7a9d85241e;login=hyeon_e_life;mod=0;msg-id=resub;msg-param-cumulative-months=14;msg-param-months=0;msg-param-multimonth-duration=0;msg-param-multimonth-tenure=0;msg-param-should-share-streak=0;msg-param-sub-plan=1000;msg-param-sub-plan-name=Channel\\sSubscription\\s(rlgus1006);msg-param-was-gifted=false;rm-received-ts=1659855421616;room-id=490638667;subscriber=1;system-msg=현이씨\\ssubscribed\\sat\\sTier\\s1.\\sThey've\\ssubscribed\\sfor\\s14\\smonths!;tmi-sent-ts=1659855420189;user-id=178885258;user-type= :tmi.twitch.tv USERNOTICE #rlgus1006 고맙다냥",

Last I remember, I believe I spoke to @zneix about this months ago. However, after taking a look around I suppose he was working on it but became busy and hadn't found the time to finish the re-work which I assume is https://github.com/Chatterino/chatterino2/tree/zneix/fix/usernotice-cleanup.