Add color tokens and use some of them in our theme

[Pururun]

Also switch to dark theme as base theme

This is part of the design system overhaul.

---

This change is 

[linear]

DROID-375 Add color tokens

Add the color tokens from the hack day.

[Rawa]

Reviewed 26 of 26 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[Rawa]

Reviewable status: complete! all files reviewed, all discussions resolved

[albin-mullvad]

Reviewed 7 of 26 files at r1, 11 of 20 files at r2, 9 of 9 files at r3, all commit messages.
Reviewable status: 28 of 29 files reviewed, all discussions resolved (waiting on @Rawa)

[Rawa]

Reviewed 1 of 20 files at r2, 4 of 4 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[Rawa]

Reviewed 2 of 2 files at r5, 3 of 3 files at r6, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @Pururun)

---

android/app/src/main/kotlin/net/mullvad/mullvadvpn/compose/component/Scaffolding.kt line 88 at r6 (raw file):

    val canScroll = lazyListState.canScrollForward || lazyListState.canScrollBackward
    val scrollBehavior =
        TopAppBarDefaults.exitUntilCollapsedScrollBehavior(appBarState, canScroll = { canScroll })

Weird that this got added to this commit? I guess because rebase is needed? 😕

---

android/lib/theme/src/main/kotlin/net/mullvad/mullvadvpn/lib/theme/color/ColorTokens.kt line 56 at r6 (raw file):

internal val md_theme_dark_onSurface = Color(0xFFFFFFFF) // MullvadWhite
internal val md_theme_dark_surfaceVariant = Color(0xFFFFFFFF) // MullvadWhite
internal val md_theme_dark_onSurfaceVariant = Color(0xFFA3ACB5) // Subtext

If SurfaceVariant is #FFFFFF then onSurfaceVariant #A3ACB5 seems to be too bright? Seems like we according to Zeplin use the PrimaryBlue or something like that?
https://app.zeplin.io/project/5f928a32fdc9962af9018d70/screen/6037df6562fa815ad838d9f7

[Rawa]

Reviewed 7 of 7 files at r7, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

[Rawa]

Reviewable status: complete! all files reviewed, all discussions resolved

[Rawa]

Reviewed 5 of 5 files at r8, 4 of 7 files at r9, 5 of 5 files at r10, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved