Squashed merge of master-sim into master.

Includes the following commits:

==

New system feature: eUICC.

Presence of this feature implies that eUICC-related APIs are expected
to function as long as an eUICC is present in the device. Note that an
eUICC may be embedded in the device but may also be removable.

==

Add empty EuiccManager API and plumbing.

==

Add stub EuiccService.

EuiccService is the class that the LPA app must implement; for now,
just define the action and priority so that the implementation can be
found. Actual methods will come later.

Also declare two relevant permissions: BIND_EUICC_SERVICE, which the
implementation must require (so that nobody else can bind to the
service directly), and WRITE_EMBEDDED_SUBSCRIPTIONS, which permits
signature|privileged apps and CTS (via development) to access
EuiccManager APIs.

==

Add UiccAccessRule based off UiccCarrierPrivilegeRules#AccessRule.

This class can be used to transfer access rules between an
EuiccService implementation and the platform.

We also add a simple encoding/decoding of a list of rules so that they
may be stored in the subscription info table.

==

Add getEid() to EuiccManager/EuiccService.

getEid() fetches the EID. It requires either a privileged permission
(READ_PRIVILEGED_PHONE_STATE) or carrier privileges on the
currently-active profile. Until there is a use case that requires
opening this up to apps with only READ_PHONE_STATE, we shouldn't do
so.

To avoid churn in the future, the API signatures for EuiccService
include a slot ID to identify which SIM slot is being used. However,
this parameter is currently not populated correctly (nor is it usable,
as no Telephony APIs accept a slot ID to address commands). There is
no need to expose it yet in the EuiccManager APIs as we expect to
follow the TelephonyManager pattern of allowing per-slot instances of
EuiccManager in the future while keeping other method signatures the
same.

==

Define Euicc UI actions in EuiccManager/EuiccService.

The EuiccManager actions are to be implemented by the platform (and
only the platform), which forwards the actions to the active
implementation.

Also, remove our explicit priority meta-data tag as we can just rely
on android:priority in the corresponding intent-filter.

==

APIs for downloading embedded subscriptions.

Includes:

-getDownloadableSubscriptionMetadata, used by the platform and LUI to
fetch metadata about a downloadable subscription. The platform will
use this to perform the necessary permission checks (only allowing
otherwise-unprivileged apps to download profiles that are permitted
per the subscription metadata), and the LUI can use this to present
the name of the profile.

-downloadSubscription, to actually perform a profile download.

The stub for startResolutionActivity is included but not implemented;
resolution activities will be handled in a follow-up change.

==

Test: TreeHugger
Change-Id: I47b1da5a69f0736012cb137e02cd6c4e07fdaace