LEWW-71 | upgrade mkdocs ver + work with us section + tf vault repo added + adding tgw, nfw and cicd diagrams + adding leverage cli section

What?

@exequielrafaela - LEWW-71 | updating material mkdocs ver + adding youtube in footer - f9df644
@exequielrafaela - LEWW-71 | work with us section updates - f5c9326
@exequielrafaela - LEWW-71 | minor adjustments to html based sections - 30a5fbe
@exequielrafaela - LEWW-71 | subscription plan update + minor sections adjustments - b5de5b2
@exequielrafaela - LEWW-71 | Adding new diagrams and files for certs and leverage-cli section - a93143f
@exequielrafaela - LEWW-71 | Adding leverage-cli section + backups section info - 9c2f01c
@exequielrafaela - LEWW-71 | Adding tgw + nfw diagrams - 4ce8723
@exequielrafaela - LEWW-71 | updating leverage-cli index - 73666fe
@exequielrafaela - LEWW-71 | adding ref architecture demo-apps diagram + eks ci-cd argocd diagram - 4c9c300

@exequielrafaela - LEWW-71 | adding ref arch vault repo sectins and files - 41895e9
@exequielrafaela - LEWW-71 | updating make approach for leverage cli one + minor updates - 72b9631
@exequielrafaela - LEWW-71 | adding vault auth info - 372dca9

Several updates need to added to the leverage documentation.