single install documentation including manual and cli

[enekofb]

We currently have two install docs:

• https://docs.gitops.weave.works/docs/enterprise/getting-started/install-enterprise/
• https://docs.gitops.weave.works/docs/enterprise/getting-started/install-enterprise-cli/

This made sense for the initial iterations of the cli but given that we are close to get day0 completed, this difference makes it difficult the user to either discover bootstrapping via cli or to decide what to use

This ticket to address that gap

AC

• created single install documentation with a single narrative and two ways to execute: manual and cli
• handle also https://github.com/weaveworks/weave-gitops-interlock/issues/609
• https://github.com/weaveworks/weave-gitops-interlock/issues/628

Notes:

Example of the info being hidden https://weaveworks.slack.com/archives/C0287UF9J9J/p1702394900287419

[enekofb]

started in this branch https://github.com/weaveworks/weave-gitops/tree/wge-3715-single-install-docs