Http.cookiejar: support file-like objects for FileCookieJar and its sub-classes

Currently, http.cookiejar only supports path-like objects for FileCookieJar and its sub-classes (MozillaCookieJar and LWPCookieJar). So there’s no clean way to load interoperable cookie format data other than from the disk. Reasoning: Cookie files can contain sensitive info, so you may not want to write it to disk. Its useful to provide the user other options to load data, other than from the disk, especially with keys/“secrets” (which cookies can contain). E.g. environment variable or standa...