[FIX] component: various issues while mounting manually components

The initial problem solved by this commit is that it was possible to get
into a situation where a mounting/rendering was started, then the component was
updated, but then another mounting operation begins, and it tries to
reuse the previous rendering operation, which is no longer uptodate.

The underlying issue is that Owl did not track properly the various
internal state change of a component.  These issue should be solved by
the introduction of the status enum, which currently tracks 6 possible
states:

- CREATED
- WILLSTARTED
- RENDERED
- MOUNTED
- UNMOUNTED
- DESTROYED

This status number replaces the isMounted and isDestroyed boolean flags.
It has the advantage of making sure that the component is in a
consistent state (it is no longer possible to be destroyed and mounted,
for example)

Another advantage is that it gives us an easy way to track the fact that
a component has been rendered, but is not in the DOM.  This is a subtle
situation where some various events can happen, and we need to be able
to react to that case.

Note that there is a change of behaviour: if a component is mounted in a
specific target, then before the mounting is complete, the component is
mounted in another target, we no longer reject the first mounting
operation.

[FIX] crash when rendering component before mounting

This commit makes sure that Owl does not crash when a component is
created, then updated (for example, with a (observed) state change), and
then, some moment later, mounted.

The initial render is not useful, because it is not linked to a mounting
action anyway.  And it caused issues such as a crash when Owl tried to
patch it to a non existing target

[REL] v1.2.2

# v1.2.2

This is just a small bug fix release, because we need it in Odoo.

Bug fix: allow renderings for detached components. Before this release, Owl
ignored renderings in some cases if a component is detached.  We now still render
it, because it is important in some cases.

[REL] v1.2.1

# Owl v1.2.1

## Changes

- fix: issue with components with shouldUpdate and remounting not rendering
- fix: issue with connected components using onUpdate callback not rendering
- fix: error in todoapp example code

[REL] v1.2.0

# Owl v1.2.0

## Changes

- translation fix for terms surrounded by spaces
- fix: properly remount components with shouldUpdate=false
- add: add two new generic hooks:  and
- fix: do not skip rendering in components using store and local state (in some cases)

Note that the last change is a pretty significant change: component connected to
a store should be very careful if the data that they represent is deleted, because
they will always be rendered with the current state of the store.

[REL] v1.1.1

# Owl v1.1.1

## Changes

- export  object to make utility functions testable
- minor doc improvements and corrections
- fix: make sure owl does not crash in iframe in private mode

[IMP] qweb: the t-slot directive is now dynamic

It is useful for some kind of components to be able to use a completely
dynamic slot expression.

[REL] v1.0.13

# Owl v1.0.13

## Bug fixes

- fix: slots: prevent infinite loop in some cases

[REL] v1.0.12

# Owl v1.0.12

## Bug fixes

- fix: properly handle named t-slots inside named t-slots
- fix: do not render comments as text in t-raw
- fix: allow dynamic template in t-call
- fix: correctly handle top-level t-call with body
- fix: correct cause of non determinism in tests

## Tooling improvements

- setup github actions for CI
- improve owl bundling pipeline
- add  flag in owl configuration
- add prettier to github CI

[REL] v1.0.11

# Owl v1.0.11

- improve release script to make sure we get correct code on npm