this patch adds support for tenants. This touches mostly pageserver.
Directory layout on disk is changed to contain new layer of indirection.
Now path to particular repository has the following structure: <pageserver workdir>/tenants/<tenant
id>. Tenant id has the same format as timeline id. Tenant id is included in
pageserver commands when needed. Also new commands are available in
pageserver: tenant_list, tenant_create. This is also reflected CLI.
During init default tenant is created and it's id is saved in CLI config,
so following commands can use it without extra options. Tenant id is also included in
compute postgres configuration, so it can be passed via ServerInfo to
safekeeper and in connection string to pageserver.
For more info see docs/multitenancy.md.
Add build dependencies and other local packages needed (Ubuntu only).
Fix some weird formatting of psql commands due to `sh` syntax
highlighting.
Improve test directions, so pytest doesn't scan the whole tree.
Drop description of the integration_tests directory since it's on its
way out.
* Add ancestor_id to pg_list->branch_list output of pageserver.
* Display branching point (LSN) for each non-root branch.
* Add tests for `zenith branch`.
Currently, the tests don't work in parallel. The tests try to create a
data directory in the same path and clash with each other. That should be
fixed, but for now, let's at least fix the instructions on how it works
now.
