doc/design: clarify the life-cycle of a design doc and update existing accordingly

[jiceatscion]

Fixes #4633

[jiceatscion]

This change is 

[FR4NK-W]

Reviewed 12 of 13 files at r1, 1 of 1 files at r2, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @jiceatscion)

---

doc/dev/contribute.rst line 205 at r2 (raw file):

  Once the implementation is deemed complete, the design document's status is changed to
  **Complete**, it is linked to the corresponding section of the index, and the

Suggestion:

Completed

---

doc/dev/design/index.rst line 35 at r2 (raw file):

  During implementation the design may also become suspended (**Postponed**)
  or abandonned (**Rejected** or **Outdated**).

Suggestion:

abandoned

[FR4NK-W]

The capitalization of the status in

• PathService.md
• forwarding-key-rollover.rst
• BeaconService.md
• ColibriService.md

could also be updated for consistency.

[FR4NK-W]

Reviewable status: 11 of 13 files reviewed, 3 unresolved discussions (waiting on @jiceatscion)

---

doc/dev/contribute.rst line 141 at r2 (raw file):

Typical examples for substantial change proposals include:

* Adding, changing, or removing compontents or functionality

Suggestion:

components

[jiceatscion]

Done

Reviewable status: 11 of 13 files reviewed, 3 unresolved discussions (waiting on @FR4NK-W)

---

doc/dev/contribute.rst line 141 at r2 (raw file):

Typical examples for substantial change proposals include:

* Adding, changing, or removing compontents or functionality

Done.

---

doc/dev/contribute.rst line 205 at r2 (raw file):

  Once the implementation is deemed complete, the design document's status is changed to
  **Complete**, it is linked to the corresponding section of the index, and the

Done.

---

doc/dev/design/index.rst line 35 at r2 (raw file):

  During implementation the design may also become suspended (**Postponed**)
  or abandonned (**Rejected** or **Outdated**).

Done.

[FR4NK-W]

Reviewed 7 of 7 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @jiceatscion)