Several fixes on landing page

[znegrin]

fix #438
fix #435

According to #435, this PR updates the landing with several changes:

Enterprise edition page

• Under "Talent Assessment & Management" the "learn more" button currently point to a "404 Not Found" instead of https://sourced.tech/solutions/talent-assessment-and-management/ (missing an s at assessment)

Community edition page

• Update the "download source{d}" button to link to https://go.sourced.tech/community-edition-download instead of https://go.sourced.tech/engine-download

Manager get started tab

• Update the "Request CE demo" link to point to https://go.sourced.tech/community-demo

Executives get started tab

• Replace the "1m video" by "Watch 1m Video" and update the title in the pop up title to "source{d}: The Data Platform for your Software Development Life Cycle'

IT Modernization & Compliance

• Update ALL the "download source{d}" buttons to link to https://go.sourced.tech/community-edition-download instead of https://go.sourced.tech/engine-download

DevOps & Cloud Native Transformation

• Update ALL the "download source{d}" buttons to link to https://go.sourced.tech/community-edition-download instead of https://go.sourced.tech/engine-download

Engineering Effectiveness & Efficiency

• Update ALL the "download source{d}" buttons to link to https://go.sourced.tech/community-edition-download instead of https://go.sourced.tech/engine-download

Talent Assesment & Management

• Update ALL the "download source{d}" buttons to link to https://go.sourced.tech/community-edition-download instead of https://go.sourced.tech/engine-download

Header & Footer

• Under Company, remove About from both Header and Footer
• Replace "Team" by "Management"
• Careers links to "offices" it's of Openings

[dpordomingo]

LGTM but one missing link

[dpordomingo]

everything ready at staging
https://landing-staging.srcd.run