feat(server): support env-based custom favicon urls

Author: ginkoid

client/src/static/.well-known/security.txt

@@ -1,4 +1,3 @@
 Contact: mailto:[email protected]
 Preferred-Languages: en
-Canonical: https://2020.redpwn.net/.well-known/security.txt
 Policy: https://github.com/redpwn/rctf/blob/master/SECURITY.md

client/src/static/favicon.ico

@@ -51,6 +51,7 @@ YAML/JSON name|environment name|required|default value|type|description
 `divisions`|_(none)_|yes|_(none)_|object|division IDs and their respective names. [documentation](management/divisions.md)
 `defaultDivision`|_(none)_|no|_(none)_|string|default division ID. [documentation](management/divisions.md)
 `divisionACLs`|_(none)_|no|_(none)_|array|ACLs for restricting division access. [documentation](management/divisions.md)
+`faviconUrl`|`RCTF_FAVICON_URL`|no|_(rCTF favicon)_|string|URL to custom favicon image
 
 ### Additional
 
@@ -65,8 +66,8 @@ YAML/JSON name|environment name|required|default value|type|description
 `email.from`|_(none)_|no|_(none)_|provider|`from:` address when sending email. [documentation](providers/emails/index.md)
 `ctftime.clientId`|`RCTF_CTFTIME_CLIENT_ID`|no|_(none)_|string|CTFtime OAuth client ID. [documentation](integrations/ctftime.md)
 `ctftime.clientSecret`|`RCTF_CTFTIME_CLIENT_SECRET`|no|_(none)_|string|CTFtime OAuth client secret. [documentation](integrations/ctftime.md)
-`recaptcha.siteKey`|`RCTF_RECAPTCHA_SITE_KEY`|no|_(none)_|string|reCAPTCHA public site key.[documentation](integrations/recaptcha.md)
-`recaptcha.secretKey`|`RCTF_RECAPTCHA_SECRET_KEY`|no|_(none)_|string|reCAPTCHA secret key.[documentation](integrations/recaptcha.md)
+`recaptcha.siteKey`|`RCTF_RECAPTCHA_SITE_KEY`|no|_(none)_|string|reCAPTCHA public site key. [documentation](integrations/recaptcha.md)
+`recaptcha.secretKey`|`RCTF_RECAPTCHA_SECRET_KEY`|no|_(none)_|string|reCAPTCHA secret key. [documentation](integrations/recaptcha.md)
 `recaptcha.protectedActions`|__(none)__|no|_(none)_|array|list of reCAPTCHA protected actions. [documentation](integrations/recaptcha.md)
 
 ### Advanced

docs/content/configuration.md

@@ -149,6 +149,7 @@ const envConfig: PartialDeep<ServerConfig> = {
     description: process.env.RCTF_META_DESCRIPTION,
     imageUrl: process.env.RCTF_IMAGE_URL
   },
+  faviconUrl: process.env.RCTF_FAVICON_URL,
   logoUrl: process.env.RCTF_LOGO_URL,
   globalSiteTag: process.env.RCTF_GLOBAL_SITE_TAG,
   email: {