website problems - broken links, mismatching claims, typo

### Steps to reproduce

See https://ralph.allegro.tech/ .

a) Section "Install Ralph" says "We provide DEB package and Docker image for your convience", but clicking through to the linked documentation page reveals "The package can be installed inside a Docker container, however at the time of this writing there is no official image yet".

b) There's a typo "convience" - should be "convenience".

c) In the "Read the documentation" section, the 3 links (REST API, transitions (workflows), DC visualization) are broken - leading to 404.