Add rewards setup panel to onboarding tour

[zenparsing]

The setup panel should allow the user to adjust the "ads per day" and "monthly AC amount" settings:

The panel should only be displayed after the user has opted-in by clicking the "Start Using Rewards" button. It should not be displayed if the user is simply previewing the tour or viewing the tour again after enabling rewards.

[LaurenWags]

Verified using

Brave	1.21.54 Chromium: 88.0.4324.152 (Official Build) beta (x86_64)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	macOS Version 10.15.7 (Build 19H512)

Verified test plan from brave/brave-core#7525

Rewards Panel

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Rewards page

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Tip Dialog

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

---

Verification passed on

Brave | 1.21.68 Chromium: 89.0.4389.58 (Official Build) (64-bit)
-- | --
Revision | 1a139f28ecc27719439e37c6b1533cee999cb802-refs/branch-heads/4389@{#1134}
OS | Windows 10 OS Version 2004 (Build 19041.804)

Verified test plan from brave/brave-core#7525

Rewards Panel

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Rewards page

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Tip Dialog

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

---

Verification passed on

Brave	1.21.68 Chromium: 89.0.4389.58 (Official Build) (64-bit)
Revision	1a139f28ecc27719439e37c6b1533cee999cb802-refs/branch-heads/4389@{#1134}
OS	Ubuntu 18.04 LTS

Verified test plan from brave/brave-core#7525

Rewards Panel

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Rewards page

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Tip Dialog

Confirmed quick tour does not contain settings slide.
Confirmed tour shown after clicking on "Start using Brave Rewards" does contain settings slide.
Confirmed able to modify the selections on the settings slide.
Confirmed selections are reflected on brave://rewards page.

Setting slide with default values	Updated settings via slide	Selections retained on brave://rewards

Logged #14368 for missing translations