Be more lenient when parsing instance URL/domain

[ShadowJonathan]

It seems that multiple users are encountering this; When pasting a URL/domain to log into, we are not very lenient when trying to resolve that URL/domain, requiring a specific setup of trailing or not-trailing paths, with or without https, andsoforth, to log in.

We should be more lenient and try more things, if the resolved domain/url does not match the string given, we should display this in small font above/under the composer, to make the user aware of any discrepancy, if it exists.

It is possible that the domain that they log into with is a different domain than the one it federates as, so we should maybe look into resolving this intelligently too, if this comes up.